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The Jewellery Buyer’s Handbook

Anna, our FGAA-qualified gemmologist, on buying finished jewellery with your eyes open — what the stamp inside the band actually means in Australia, how to read a mount at ten times magnification, and where the tenfold price spreads really come from.

Written by , FGAA-qualified gemmologist · Ministry of Gems®, Sydney
9 chapters · 8,227 words · about 36 minutes
Gemmologically reviewed August 2026 · free to read, free to download, free to share

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I Foreword: The Anatomy of an Honest Jewel

Anna, our FGAA-qualified gemmologist, on why a finished jewel is the hardest thing in the trade to judge honestly — and what to look at first when the shop lighting is doing its best to stop you.

A loose gemstone is an honest object. You can turn it, weigh it, measure its refractive index, put it under a microscope and, within a few minutes, tell most of the truth about it. A finished jewel is the exact opposite, and that is what makes it the hardest thing in this trade to judge fairly. By the time a ring reaches a display case, almost everything that determines its value has been hidden from you. The stone is behind metal. The metal is behind polish. And the workmanship — the part that actually decides whether the piece survives twenty years of being knocked against door frames and car keys — lives on surfaces you cannot see without turning the thing upside down, which is not a natural thing to do while somebody is watching you hopefully from the other side of a counter.
Then there is the light. Retail jewellery lighting is engineered, and engineered well: tight beams, high colour temperature, a great deal of sparkle bouncing off mirrored trays. A stone that looks alive under a halogen spot can look flat beside a window. A rhodium finish that reads as immaculate under a downlight will show every thin patch the moment you carry it outside. None of this is a conspiracy — shops light stock to sell stock, and a badly lit jewel sells to nobody — but it does mean that the environment in which you make the decision is not the environment in which you will wear the thing. Ask to take the piece to a doorway. Any seller worth buying from will hand it to you.

The three questions I ask before I reach for a loupe

The first is: what is the metal, and who says so? Not what is stamped inside the band, which is a different question entirely, but what independent basis exists for believing the stamp. The second is: what holds the stones in, and how well was it made? Prongs, beads, bezels, clasps and the small architecture underneath a setting are where jewellery fails, and they are also where a maker who is cutting corners will cut them first, because almost nobody looks. The third is: what is in this piece that nobody has certificated? A centre stone may arrive with a laboratory report. The forty small diamonds around it almost certainly will not, and — as Chapter VI sets out — that gap has consequences that most buyers have never been told about.
In Australia, the first of those three questions has an uncomfortable answer, and I would rather you heard it from me than discovered it later. This country has no compulsory hallmarking scheme and no government assay offices. The 750 or the 9ct inside your ring was, in the overwhelming majority of cases, struck by the person who made the piece. It is a claim, not a certification. That is not a scandal and it does not mean Australian jewellery is dishonest — most of it is entirely honest — but it does change what a stamp is worth as evidence, and it changes where your protection actually comes from. Chapter II is about exactly that, and it is the chapter I would read first if you only read one.

What this book will and will not do

There are nine chapters. They run in the order a purchase actually happens: what the marks mean, what the metal is, how the piece was manufactured, how to inspect a setting in ten minutes with a cheap loupe, what to ask about the stones, how to get the fit right before you pay rather than after, where the price comes from, and what paperwork and legal rights you walk out with. Metal gets a chapter here rather than a book, because it already has a book — The Gold & Precious Metals Handbook goes considerably deeper into alloys, plating and testing than this volume needs to. Likewise, if what you are buying is a coloured stone in a mount, the Online Gem Buyer's Handbook and the Certification Handbook sit beside this one on the same shelf, and all of them are free.
Every date, figure, percentage and standard in the pages that follow traces to a named source, and I have put the names in the prose rather than burying them: the Gemological Institute of America, CIBJO, the four United Kingdom assay offices, the International Hallmarking Convention, the United States Federal Trade Commission, the Australian Competition and Consumer Commission, the Australian Taxation Office, the National Council of Jewellery Valuers. Where a number is a trade estimate rather than a published measurement — retail markup figures are the obvious case — I say so in the sentence rather than dressing an estimate up as a fact. Where the trade genuinely disagrees with itself, and on caratage and prong counts it does, I show you both sides.

A word on candour

You will find no sneering here at lab-grown stones or at plated goods. A laboratory-grown diamond is a real diamond, a gold-plated chain is a real object that does a real job at a real price, and both are entirely legitimate products when they are described accurately. Our position is simply that the description has to be accurate and it has to be volunteered rather than extracted. What I object to is undisclosed synthetic melee sold as natural, hollow work sold as solid, and an in-house valuation waved about as though it were an independent grading report. Those are not matters of taste. Every stone we sell is assessed in-house by our FGAA-qualified gemmologist, with full treatment disclosure and a Digital Gemstone Passport, because that is the standard I would want applied to something I was buying.
Read this with a cup of tea and, if you can, beside a south-facing window — we are in the southern hemisphere, and south-facing light is the steady, indirect daylight that flatters nothing. That is the light I use at the bench in Sydney, and it is the light in which a jewel tells you the truth about itself.
— Anna, FGAA
Ministry of Gems, Sydney

II The Stamp That Is Not a Hallmark

Australia has no compulsory hallmarking and no assay offices, so the 750 inside your ring is a claim by the maker rather than an independent certification — here is what that means, and what the UK, the Vienna Convention and CIBJO do instead.

Begin with the word itself, because it is routinely misused in Australian shops. A hallmark, properly, is a mark struck on an article by an independent authority that has tested the metal. It is not a maker's logo, not a caratage number, and not a country-of-origin stamp. If nobody independent has assayed the metal, whatever is stamped inside the band is a description — and a description is only as good as the person who wrote it. That distinction is the whole of this chapter, and it is the single most useful thing I can teach an Australian buyer.

What Australia actually has

Australia has no compulsory hallmarking scheme and no government assay offices. Marking of precious-metal jewellery here is voluntary and, in practice, almost always applied by the manufacturer to its own work. We did briefly have commercial hallmarking bodies — the Sydney Hall Mark Co. and the Commonwealth of Australia Hall Mark Co. operated from 1923 to 1928, and their records survive in the collector literature catalogued by LAPADA — but that was a short-lived private scheme, not a legal system, and nothing replaced it. The nearest thing we have today is the Gold and Silversmiths Guild of Australia, formed in 1988, which, on its own account, administers the only comprehensive voluntary marking scheme in the country: members' marks record maker and material, optionally a date, alongside the Guild's kangaroo-head mark, and members' maker's marks are recorded by impression on fine-silver touchplates held by the Guild. That register is a genuinely useful thing, and a Guild mark is worth more to you than a bare number. But it is voluntary, and most jewellery sold in Australia does not carry one.
So what protects you? Not an assay office, but the Australian Consumer Law. Describing metal falsely is a misleading representation, and the Australian Competition and Consumer Commission enforces that prohibition in this industry rather than a technical marking standard. The ACCC's jewellery-industry publications, first issued in 2005, set out the same logic for stones: calling cubic zirconia a diamond of any kind, or failing to disclose a gemstone treatment, risks breaching the law, and terms such as cultured, imitation, synthetic and created are expected to be used precisely. Enforcement is real rather than theoretical — the ACCC has twice brought Federal Court proceedings over two-price advertising against operators of the same national jewellery chain, with penalties of $380,000 in 2008 across eleven catalogue items and $250,000 in a 2012 judgment, upheld on appeal in 2013, over misrepresented savings on forty-four items. The lesson for a buyer is that the law here works after the fact, on evidence, and that it is triggered by documents. Which is why Chapter IX is about paperwork.

What a hallmark looks like where they are compulsory

The United Kingdom is the contrast worth knowing, because a great deal of jewellery in Australian estate cabinets came from there. Under the Hallmarking Act 1973 it is a criminal offence, in the course of trade, to describe an unhallmarked article as wholly or partly gold, silver, platinum or palladium, or to supply it with such a description; dealers must also display a statutory notice explaining the marks. Four assay offices — London, Birmingham, Sheffield and Edinburgh — test and strike the marks independently before sale. A compulsory British hallmark has exactly three components: the sponsor's or maker's mark, the millesimal fineness mark, and the assay office mark. The date letter and the traditional pictorial fineness symbols, which is what most people picture when they imagine a hallmark, became voluntary from 1 January 1999. Small articles are exempt by weight: below 1 gram for gold, 7.78 grams for silver, 0.5 gram for platinum and 1 gram for palladium.
Above that sits the International Hallmarking Convention, opened in 1972 and in force from 1975, which gives around twenty member states a mutually recognised Common Control Mark so that an article assayed in one member country can be sold in another without re-testing. Australia is not a member. And running underneath all of it is CIBJO, the World Jewellery Confederation, whose Precious Metals Blue Book recognises the finenesses 999, 986, 916, 750, 585, 416, 375 and 333 and — the sentence to remember — permits no negative tolerance at all. A piece stamped 750 should assay at 750 or better, not at 748. That is an international trade norm you can hold a seller to in writing, whatever the local marking law says.

The American answer, and one word to distrust

The United States, like Australia, has no compulsory hallmarking; instead the Federal Trade Commission governs description through the Jewelry Guides at 16 CFR Part 23. The 2018 revision matters, because most older advice is now wrong: alloys below ten karat may be called gold provided the karatage is disclosed, so 8K gold is a lawful description there. The Guides also prohibit marking a hollow-centre article solid — the correct form is something like 14 Karat Gold-Hollow Center — and they set hard minimums for coatings: gold plated requires at least 0.175 micron of ten-karat-or-better gold applied electrolytically, gold filled requires a mechanically bonded ten-karat-or-better layer with the fineness stated, and vermeil requires a sterling-silver base under at least 2.5 microns of ten-karat-or-better gold. Those are the most precisely quantified coating definitions I am aware of in any published trade rule, which is why I quote the FTC Guides to Australian clients even though they are American.
Which brings me to the word solid. In American usage it is regulated and means not hollow. In Australian retail speech it is used loosely to mean not plated, and it has no local legal definition at all. So a buyer reading American advice in an Australian shop, or the reverse, is being told two different things by the same syllable. Do not argue about the word. Ask instead, in writing, for the fineness, the finished weight in grams, and whether any part of the article is hollow, tubed or electroformed. Three factual answers close the gap that one ambiguous adjective opens.

III Metal in Brief: Caratage, Colour and the Cost That Comes Later

The 9ct-versus-18ct argument settled against the Vickers hardness data, what rhodium plating really costs over a decade, and the nickel rule Europe has and Australia does not.

Caratage is a proportion, nothing more. Twenty-four parts is the whole; 18 carat is eighteen parts gold in twenty-four, which is 750 parts per thousand and why the stamp reads 750; 9 carat is nine parts in twenty-four, 375 per thousand, 37.5 per cent gold. Everything else in the alloy is other metal — copper, silver, zinc, palladium, nickel, in proportions the maker chooses — and it is that other 62.5 per cent, not the gold, that decides how a 9 carat ring behaves on a hand. This chapter is deliberately short, because metal has a volume of its own; if you want alloy chemistry, testing methods and the full plating ladder, The Gold & Precious Metals Handbook is where it lives. What follows is only what you need in front of a display case.

The 9ct question, settled against the data

The most repeated claim in Australian jewellery retail is that 9 carat wears better than 18 carat. The metallurgy does not support it. On the Vickers hardness scale, 18 carat alloys typically run about 135 to 165 HV, against roughly 80 to 120 HV for 9 carat, depending on the specific alloy and its condition. Eighteen carat is the harder metal, measurably, and the Sydney jeweller Larsen and others have been saying so publicly for years. Nine carat is also more brittle, because 62.5 per cent of it is base and white metals: it is more prone to stress-cracking at solder joints, and it tarnishes faster, since those base metals react with sweat, chlorine, perfume and household chemicals in a way that gold does not.
The trade is genuinely split on this, and I will not pretend otherwise — several respected Australian retailers still recommend 9 carat as the practical everyday choice, on cost and on scratch resistance. The honest resolution is that the two metals fail differently. Nine carat scratches marginally shallower; 18 carat dents and survives. Nine carat cracks where 18 carat bends. Neither is a durability free lunch, and the variable that dominates both of them is construction quality — a well-made 9 carat ring will outlast a badly cast 18 carat one every time, which is the subject of the next chapter. Buy 9 carat if the budget says so and buy it without embarrassment. Just do not buy it because somebody told you it is tougher.

White gold is a maintenance contract

There is no such thing as white gold in the sense most buyers imagine. Gold is yellow; white gold is a gold alloy bleached toward grey by white metals and then, almost universally, electroplated with rhodium to give it the bright cold whiteness people actually want. Rhodium wears off. On a daily-worn ring the trade norm is replating every twelve to twenty-four months, at roughly US$60 to US$150 a service, and while some pieces stretch to three years, the shank and the underside of a setting are where it goes first. Run that out over a decade of ownership and you are looking at somewhere between five and ten services, depending which end of that interval your wear pattern lands on. It is not ruinous, but it is a recurring cost that platinum simply does not have, and it is almost never quoted at the point of sale.
This is worth building into the comparison rather than discovering later. If you are weighing an 18 carat white gold setting against platinum, the platinum premium at purchase is partly a prepayment of maintenance you would otherwise pay in instalments — and platinum's own drawback, expensive resizing, is covered in Chapter VII. If you love the warm tone anyway, yellow and rose gold need no plating at all, which is the quietest cost saving in the shop. And if you are buying white gold, ask two questions before you pay: does the seller replate, and at what price? A jeweller who quotes you a figure without flinching is telling you they expect to see you again.

Nickel, skin, and the standard Australia does not have

Some white alloys use nickel as the whitening metal, and nickel is the commonest contact allergen in jewellery. The European Union regulates it: under REACH Annex XVII, item 27, tested to the EN 1811 method, nickel release is limited to 0.5 micrograms per square centimetre per week for articles in prolonged contact with skin, and 0.2 micrograms for piercing posts. Australia has no equivalent mandatory nickel-release standard. That is a genuine gap rather than a rhetorical one, and it matters most for anyone who has reacted to costume jewellery, to a watch back or to an earring post before.
The practical response is not alarm but specification. Ask what the white alloy is whitened with. Palladium-whitened white gold and platinum both avoid the problem entirely; a nickel-free alloy should be described as such on the sales documentation, not merely mentioned across a counter. For earrings, which sit in broken skin, this is not a preference, it is a medical question, and any seller who is vague about it is telling you they do not know their own supply chain. Rhodium plating incidentally provides a barrier while it lasts — but it is a barrier with a service interval, which brings us back to the paragraph above.
One last piece of arithmetic. Metal is a bigger share of what you are paying than it used to be, because spot gold traded around US$4,600 an ounce on 21 August 2026, up roughly 37 per cent year on year on the Trading Economics series. That has two consequences for a buyer. It makes the finished weight in grams a number worth having in writing, because you can do the metal maths yourself. And it makes hollow and lightweight construction commercially far more attractive to manufacturers than it was five years ago — which is precisely why the next chapter exists.

IV How a Jewel Is Actually Made

Cast, die-struck or hand-fabricated — the three ways a piece of jewellery comes into the world, the porosity and grain-size differences behind them, and the loupe tells that give a mass-cast mount away in ten seconds.

Two rings can share a caratage, a stone weight and a silhouette and be different objects, because they were born differently. There are three routes from raw metal to finished jewel and they are not interchangeable. Casting pours molten metal into a mould. Die-striking hammers solid metal into shape under enormous pressure. Hand fabrication builds the piece from wire, sheet and forged components, joined at the bench. Every mount you will ever be shown is one of those three, or a hybrid, and the difference is visible at ten times magnification once you know what you are looking at.

Casting, and what porosity actually costs you

Lost-wax casting is the dominant volume-production method and has been for decades. A wax model is invested in plaster, the wax is burnt out, molten metal fills the void. It is fast, it reproduces fine detail cheaply, and a well-run casting house produces excellent work — I want to be clear that cast is not a synonym for bad. But the process has two characteristic defects that the technical literature, including United Precious Metal Refining's troubleshooting guide for the trade, describes plainly: gas porosity and shrinkage porosity. Both leave pits and voids inside the metal. Those voids reduce the effective load-bearing cross-section of a prong or a shank, they concentrate stress where the metal is thinnest, and they degrade both polish and long-term durability. A prong with a void in it is a prong that will snap earlier than its dimensions suggest.
Worked metal is denser. Die-striking presses a blank under tens of tonnes of pressure, which closes porosity and tightens the grain structure; forging and hand fabrication do the same thing more slowly. The numbers are the clearest way to see it: cast metal has a grain structure running roughly 50 to 200 microns, randomly oriented, while struck or worked metal runs about 10 to 50 microns, aligned by the direction of working. The Stuller bench literature and makers such as Whitehouse Brothers, who die-strike their bands, give the practical consequences — higher strength, better corrosion resistance, and crucially better spring in prongs and clasps. Spring is what lets a prong tip be bent over a stone and stay bent, and what lets a clasp close ten thousand times without gaping. It is the property you feel when a good piece simply feels tight.

The ten-second loupe tells

You do not need a microscope to tell low-grade mass casting from careful work. Turn the piece over and look at the surfaces nobody polishes for the photograph. The tells, catalogued in the trade's own quality-control literature, are these: pitting or porosity visible on inner surfaces; an unpolished under-gallery, still grey and rough from the mould; parting or mould lines left running along the shank; solder blobs at joins where a bench jeweller should have filed and finished; and rounded, mushy detail where a crisp hand-cut edge belongs — millegrain that has lost its beading, engraving that has lost its shoulders.
The gallery deserves its own sentence, because it is the most honest surface on a ring. The gallery is the under-structure that connects the head holding the stone to the shank you wear. In fine work it is pierced, finished and polished, and it is visible from the side; open gallery work lets light reach the pavilion of the stone and lets the piece be cleaned properly, which matters more than any of it, because a mount that cannot be cleaned will be dull within a year. An unfinished, clogged or blob-like gallery is a mass-production tell that no amount of top-surface polishing hides. Look under the stone. Sellers rarely expect it, and good ones enjoy it.

Hollow, electroformed, and the honest version of cheap

Hollow and electroformed pieces are built around a void — a formed shell rather than a solid body. They use 50 to 70 per cent less gold than a solid equivalent, with wall thicknesses of roughly 0.5 to 1 millimetre. That is a real engineering answer to a real problem: with metal at present prices, hollow construction is one of the few ways to make a substantial-looking chain at an accessible price. Manufacturers position it as sensible value engineering, and within its limits they have a point.
The limits are hard, though. Thin walls dent — a hollow chain can be deformed by a firm squeeze between finger and thumb — and once dented they often cannot be repaired, because soldering heat melts straight through the wall. Bench jewellers who spend their working lives refusing those repairs are considerably less enthusiastic than the marketing. Both positions are defensible; what is not defensible is failing to disclose which one you are buying. Under the American FTC Guides, marking a hollow-centre article as solid is a misrepresentation, and the correct description names the construction. Australia has no equivalent rule, so you must ask. Get it in writing that the article is solid, or accept in writing that it is hollow and buy it as the consumable it is rather than the heirloom it resembles.

V Settings, Prongs and Clasps: The Ten-Minute Inspection

Four prongs or six, what a good bead looks like at 10x, why the gallery under the stone is the most honest surface on a ring, and the clasp hierarchy that predicts whether you will ever lose the chain.

Everything in this chapter can be done standing up, in a shop, with a ten-dollar loupe and no gemmological training. It takes about ten minutes and it is the highest-yield ten minutes available to a jewellery buyer, because settings are where jewellery actually fails. Stones are hard; metal is not. Diamonds do chip — almost always at the girdle — but in my experience a stone is far more often lost because a prong tip wore thin, a bead was never properly raised, or a spring ring opened in a coat pocket.

Prongs: count is a size question, maintenance is the real one

GIA's own consumer guidance frames the trade-off cleanly. A six-prong setting protects the girdle of the stone better and retains the stone if one prong fails; a four-prong setting shows more of the stone and suits smaller stones. The rule of thumb that follows is size-dependent rather than absolute: under about a carat, four prongs are standard and entirely sound; between one and two carats either is defensible; above about two carats six prongs, or a bezel, is the conservative choice. The trade is not unanimous even here — plenty of experienced bench jewellers will tell you a well-made four-prong head under two carats is secure for decades, and they are right.
Which is why the count is the smaller variable. The larger one is maintenance. Prong tips wear from the outside in, invisibly, over years of contact with fabric and benchtops, and the failure is sudden when it comes. Annual inspection and re-tipping before the tips get thin is worth more than two extra prongs. So the question to ask the seller is not only how many prongs, but whether they inspect and re-tip, how often they recommend it, and what it costs. At the counter, look at each tip through the loupe: a healthy tip is a rounded, substantial cap sitting visibly over the stone, not a flattened sliver you can see daylight beside. Then press gently on the stone with a fingernail and listen. A secure stone is silent. A faint tick is a stone moving in its seat, and it means the piece goes to a bench before it goes home.

Bezels, baskets and the geometry of not snagging

A bezel wraps the girdle in a continuous collar of metal. It is among the most secure of the common settings, it protects the girdle from the chips that end stones, and it suits hands that work — although it hides more of the stone and reflects less light into it. A basket setting sits between the two: it is a prong setting with a horizontal gallery rail forming an openwork basket beneath the girdle, which adds lateral security and lowers the snag profile compared with a plain cathedral head. If you catch settings on knitwear, that geometry is the fix. Whatever the style, run the piece across the sleeve of your jumper before you buy it. A mount that grabs wool in a shop will grab everything for the rest of its life.

Pavé at ten times magnification

Pavé is where quality separates most visibly, because it is fiddly, slow handwork that machines have not replaced. In proper pavé and micro-pavé each stone sits in its own carved seat and is locked down by raised metal beads worked up out of the surrounding metal and pushed over the girdle. Three loupe checks tell you nearly everything. First, are the beads present and symmetrical — typically three or four to a stone depending on the layout, evenly placed, each one a distinct rounded ball rather than a smear? Second, is any bead thin, flattened or missing? Third, are the stones level with each other and evenly spaced, or does the line wander and dip?
Lost pavé stones are not an indictment of the style; they are an indictment of the bead work. The stones that fall out are the ones whose beads were badly raised or have worn away, which is why the same style can be flawless from one workshop and a slow-motion disaster from another. If you are looking at a heavily set band, ask who set it and whether it is guaranteed against stone loss, and for how long. An honest answer to that question, in writing on the receipt, is worth more than any adjective in the catalogue.

Clasps: the fastest hand-check of build quality

A clasp is a small machine, and a maker who has skimped anywhere will usually have skimped here. The security hierarchy runs, from best down: a box clasp fitted with a safety figure-eight, then a lobster claw, and last a spring ring — the weakest of the common clasps, which belongs only on light chains. Toggles and hooks sit outside that ranking; they rely on the weight of the chain to stay closed, which makes them a styling choice rather than a security one. The other rule is mass matching: the clasp should be proportionate to the chain it holds. A heavy chain closed with a small spring ring is a chain you will eventually lose, and the mismatch is visible from a metre away once you have seen it once.
Operate the clasp several times before you buy. It should open with a definite resistance and close with an audible, clean click, and the two halves should have no lateral play when closed. On a lobster claw, look at the tiny spring lever — it should return sharply, not sluggishly. On a box clasp, check that the safety catch actually engages rather than merely resting. Then check the jump rings at each end of the chain: they should be soldered closed, not sprung open, because an unsoldered jump ring is a clasp failure waiting for a different excuse. Ten minutes, no training, and you will have learned more about the piece than the display card will ever tell you.

VI The Stones in the Setting: Centre, Melee and What Nobody Certificates

The centre stone gets a report from 0.15 carat upward; the melee almost never does — and GIA's own laboratory findings show why that gap matters more than most buyers realise.

A finished piece usually contains two populations of stone with entirely different paperwork. There is the centre, which may well arrive with an independent laboratory report and a stone-by-stone description. And there is everything else — the halo, the shoulders, the band, the accents — which almost certainly does not. Most buyers assume the report covers the ring. It covers one stone in the ring, and understanding that boundary is the difference between an informed purchase and a hopeful one.

The certificated centre

GIA issues diamond grading reports from 0.15 carat upward, and defines melee as diamonds under one-fifth of a carat. So 0.15 carat is GIA's floor, and in practice the weight below which stone-specific independent paperwork becomes rare. For a centre stone at or above that weight, an independent report from a recognised laboratory is the standard to insist on, and the word independent is load-bearing: an in-house certificate written by the seller, or an in-house valuation quoting a figure conveniently above the price, is not independent grading and should never be treated as though it were. Ask which laboratory, ask for the report number, and check the number against the laboratory's own online database before you pay rather than after. One note of candour: GIA has been migrating its small-stone report products toward digital formats, so the physical article you receive may differ from older descriptions — the 0.15 carat floor is the stable fact, the paper format is not.

The melee nobody grades

Melee is almost never individually graded, as a matter of economics — grading a 0.01 carat stone costs more than the stone. That leaves a verification gap in every diamond-set mount on the market, and the gap has been documented from inside the laboratory system. GIA's Mumbai laboratory found 101 undisclosed CVD synthetic diamonds in a single 323-stone melee parcel, roughly 31 per cent of the parcel, and in another parcel reported in GIA's Gems & Gemology lab notes only one stone out of 1,093 was natural. Those incidents date from 2017 and 2018; the underlying risk has not gone away, which is precisely why GIA now runs an automated melee analysis service that screens natural from laboratory-grown and treated stones at 1,800 to 2,000 stones an hour. The existence of industrial-scale screening is itself the proof that the trade takes the contamination problem seriously.
None of this makes laboratory-grown melee a bad product. It is a real diamond, sold honestly every day at a sensible price, and a ring set with disclosed lab-grown accents around a natural centre is a perfectly respectable object. The problem is the undisclosed version, where you pay natural prices for something else and nobody in the chain necessarily knows. So the question to put to the seller is the one GIA itself recommends: what backs the melee? Acceptable answers include screening by a named service, a supplier declaration held on file, or a plain statement that the accents are laboratory-grown. An unacceptable answer is a shrug, and a worse one is offence taken at the asking.

What total carat weight hides

Total carat weight is the most effective legal fog in jewellery advertising. A ring advertised at two carats total might hold a 1.5 carat centre with a light halo, or a 0.4 carat centre buried in forty accent stones — and those two rings are not remotely the same purchase, because small stones are worth dramatically less per carat than one large stone of the same quality. GIA's grading guidance distinguishes carat weight per stone from total weight for exactly this reason. So the first thing to extract from any multi-stone piece is the centre-stone weight, stated separately, in writing. If a seller quotes only TCW and resists breaking it out, that resistance is your answer.
The same discipline applies when the accents are coloured rather than white. Small sapphires, rubies and emeralds set as side stones are bought by the parcel, matched by eye, and almost never accompanied by anything stone-specific — and coloured melee carries a treatment question that white melee does not, since routine heat, diffusion and fracture filling all live at that end of the market. Ask whether the accent stones are natural, whether they are treated, and whether the answer is a supplier declaration or a guess. A seller who has never thought about it will tell you so in the first three seconds.

Treatment disclosure applies inside a mount too

A sapphire does not stop being a treated sapphire because it has been set. The disclosure principle is the same in a finished ring as on a loose parcel: the American FTC's consumer guidance requires disclosure of treatments that are not permanent, that create special care requirements, or that significantly affect value, and the ACCC's Australian jewellery publications set the same expectation of precise language here. In the United Kingdom the National Association of Jewellers publishes a member guidance note on gemstone description and treatment disclosure, revised to version 2 in April 2024, which is a useful benchmark for what a candid seller volunteers before being asked. Get origin, weight, treatments and care requirements written onto the sales documentation. Our own treatment register and gem lexicon exist so that the vocabulary is not a barrier, and every stone we set is disclosed in full on its Digital Gemstone Passport.

VII Fit: Sizing, Resizing and the Decision You Make Before You Buy

Three sizing systems, one conversion anchor, a finger that changes size by two millimetres a day, and the resizing limits that are decided by construction long before you walk into the shop.

Fit is treated as an afterthought — something the jeweller sorts out later — and for a plain band that is roughly true. For anything else it is a purchase decision, because the construction of the ring you choose determines how much adjustment is physically possible, and on some of the most popular styles the answer is none at all. Deciding fit before you pay costs you five minutes. Discovering it afterwards can cost you the ring.

Three systems, one anchor to memorise

There are three sizing systems in common use and they do not resemble one another. The United States and Canada use numbers. The United Kingdom, Australia and New Zealand use the same letter system, A through Z, with half steps. Europe uses ISO 8653, where the size is not a code at all but a measurement: the inner circumference in millimetres, so EU 54 means 54 millimetres around the inside. The conversion arithmetic is simpler than the charts make it look. One UK or Australian letter step is about 1.27 millimetres of circumference; one whole US size is about 2.5 millimetres, which is why a US whole size is worth roughly two and a half letter steps. The single anchor worth carrying in your head is this: US 7 is approximately AU and UK N and a half, approximately EU 54.4, and an inner diameter of about 17.3 millimetres. From that one point you can navigate any chart you are handed, and catch the error when an overseas seller converts badly.
Measure the inner diameter of a ring that already fits, in millimetres, and multiply by pi if you want the circumference — that number, in the ISO system, is your size. It is far more reliable than the printed paper strips, which stretch, and than string, which stretches worse. If you are buying remotely, ask the seller for the inner diameter of the ring in millimetres rather than for its nominal size, because that is the only figure with no translation loss in it.

The finger that changes size

A finger is not a fixed object. Circumference varies through the day and with temperature by as much as about two millimetres — which, at about 1.27 millimetres to the letter, is well over a full letter step of swing. Fingers are smallest on cold mornings and largest in the evening and in heat, and they respond to salt, exercise, altitude, alcohol and pregnancy. The practical rule is to measure late in the afternoon or in the evening, at normal body temperature, never with cold hands, and ideally more than once on different days. A ring sized on a July morning in Melbourne will be a different ring in February.
Two width caveats. Comfort-fit bands, which have a domed inner surface, sit looser than standard-fit bands at the same nominal size, and the common trade rule is to order about half a size smaller — but only if you were measured on standard sizers, and not for bands eight millimetres wide or wider, which already fit tightly and are usually ordered at standard size or larger. If the shop measured you on comfort-fit sizers, no adjustment applies at all; ask which sizers were used. And for a large knuckle, take two measurements — one at the knuckle, one at the base of the finger — and size between them, so that the ring clears the knuckle without spinning freely below it. Sizing beads or a fitted adjuster added afterwards solve the remaining wobble.

Resizing limits are decided by construction

Here is the part that belongs in the buying decision rather than the aftercare conversation. A plain solid band can usually be resized one to two sizes safely. A pavé or side-stone shank takes about half a size to one size before the beads begin to loosen and stones start to sit unevenly. A half-eternity ring takes about one size. A full eternity ring effectively cannot be resized at all, because there is no plain metal to cut and rejoin and shortening the band would break the ring of stones. A tension-set ring cannot be resized either, because the tension calibration is the setting — alter the shank and you alter the grip on the stone. Every resize also work-hardens the metal it touches, so a shank that has been up and down repeatedly is a weaker shank than one that has never been cut.
Metal changes the economics as well as the possibility. Platinum resizing typically costs two to three times gold resizing, and the reason is physical: platinum melts at about 1,768 degrees Celsius against about 1,064 for gold, works dead rather than flowing, and generally wants a laser welder and a specialist bench. That is not an argument against platinum, which is a superb ring metal that needs no plating. It is an argument for getting platinum sizing right the first time, and for budgeting the difference if you are buying into an uncertain size — a proposal ring bought as a surprise being the obvious case.
If the piece is being made rather than bought off the tray, all of this becomes a design conversation instead of a constraint, which is one of the honest advantages of commissioning. When we build something through design your ring, sizing tolerance is settled in the drawing stage — whether the shank stays plain at the base for future adjustment, whether the eternity should in fact be a half-eternity, whether a hinged shank earns its complexity. Those are cheap decisions on paper and expensive ones in metal.

VIII Price Anatomy: Why Two Identical Rings Differ Tenfold

Spot gold near US$4,600 an ounce, keystone and triple-keystone markups, margins that hide in the melee rather than the certificated centre, and the arithmetic that explains a tenfold spread between two rings that look identical.

Two rings sit side by side. Same silhouette, same apparent stone size, same colour of metal. One is A$1,800 and the other is A$18,000, and the shop assistant explains the difference in adjectives. This chapter replaces the adjectives with a cost stack, because every component of a jewellery price is separately checkable if you know what the components are.

The cost stack

The price of any finished piece is built from six layers: metal weight multiplied by the spot price, plus the centre stone, plus the melee, plus labour for casting or fabrication and setting and finishing, plus business overhead, plus margin. Start at the bottom, because metal is the one layer you can price yourself. Spot gold traded around US$4,600 an ounce on 21 August 2026 on the Trading Economics series, up roughly 37 per cent year on year, so metal is a materially larger share of a finished piece today than the historical norm. Ask for the finished weight in grams and the caratage; a troy ounce is 31.1 grams, and 18 carat is 75 per cent gold by weight. Five grams of 18 carat therefore carries about 3.75 grams of gold, which at that spot is roughly US$555 of metal. That number will not be the price, and it should not be — but it tells you whether metal is five per cent of what you are being asked or fifty.
Labour is the layer buyers most consistently undervalue. A hand-fabricated mount with a pierced gallery and hand-raised pavé represents days of skilled bench time; a mass-cast mount with machine-set accents represents minutes. That is a legitimate multiple, and it is where the honest half of a tenfold spread comes from, along with stone grade, metal weight and whether the piece is solid or hollow. The dishonest half comes from somewhere else.

Keystone, triple keystone, and why no single markup number is honest

Keystone — doubling the wholesale cost — remains the standard bricks-and-mortar retail markup, and triple keystone is common in mall and brand retail, with branded luxury houses running higher again. You will also see the claim that wholesale diamond prices sit 30 to 50 per cent below retail in 2026, wider still for lab-grown and for melee, and that the trade prices against the Rapaport Price List, a subscription benchmark running roughly US$180 to US$250 a year. All of those figures circulate simultaneously and all of them are true of different segments, which is why no single jewellery markup number is honest. Certificated large diamonds are now thin-margin and price-transparent, because anyone can compare them. Mounts, melee-set bands and uncertificated coloured pieces are where the fat sits.
The pattern to internalise is that markup runs inverse to stone size. One widely cited retailer-education estimate puts margins at roughly 50 per cent on large certificated diamonds against 300 to 400 per cent on melee and small stones — and I flag that as a trade estimate rather than a measured figure, because it is exactly the sort of number that gets repeated without a source. Directionally it matches the wholesale-to-retail gap data, and it matches what I see. The consequence for a buyer is counter-intuitive: the certificated centre stone, the thing you were most worried about overpaying for, is usually the most competitively priced object in the ring. The halo is not.
This is why the useful question in a shop is never how much discount can you do. It is: what is the finished gram weight, what is the centre stone and does it have an independent report, what backs the accent stones, and was the mount cast or fabricated. Four answers rebuild the cost stack from the inside, and a seller who can give all four quickly is usually a seller whose price is defensible.

Valuation is not value

Insurance replacement valuations routinely exceed the purchase price, and there is a legitimate reason: a replacement valuation prices what it would cost to replace the piece at full retail, at today's metal and stone prices, often through a jeweller who did not sell it to you. It is not an estimate of what you could sell it for. Actual resale typically runs 50 to 70 per cent below the retail purchase price. So a certificate stating that your ring is worth double what you paid is not a windfall, and presenting it as one — appraised at twice the price you paid — is a documented sales tactic rather than free value. Insure at genuine replacement cost, take valuation questions to a qualified valuer, and treat any purchase framed as a financial gain with scepticism. Nothing in this handbook is financial product or investment advice, and jewellery should be bought to be worn.
One last red flag, because it is the best-documented deception in Australian jewellery retail: the perpetual sale. Two-price advertising — a was price that nothing ever actually sold at, beside a now price that is simply the price — has produced repeated Federal Court penalties in this industry, secured by the ACCC. A catalogue that is 50 per cent off every week is not discounting anything. The honest test of a price is not the number crossed out beside it; it is the cost stack above, item by item, in writing.

IX Where to Buy, What to Keep, and How to Complain

Auction premiums, imported-goods GST, lay-by rules, the receipt that triggers every remedy you have, and the Australian Consumer Law rights that survive even a six-figure purchase — plus the red flags I would walk away from.

Where you buy changes what you are buying: it changes the price arithmetic and, more importantly, the rights that attach. The same ring bought from a shop, an auction room, an overseas website and a stranger on a marketplace is four different transactions in law. This chapter is the practical end of the book: the venues, the paperwork, and what to do when something goes wrong.

Venues and what each one actually costs

Auction is where the arithmetic surprises people, because the hammer price is not the price. Christie's buyer's premium, effective from September 2025, begins at 27 per cent of hammer to US$1.5 million, then 22 per cent to US$8 million and 15 per cent above. Sotheby's raised its base rate to 28 per cent under approximately £1.5 million from 13 February 2026. Add local taxes and shipping and a hammer bid of A$10,000 is comfortably an A$13,000 purchase. Then there is the legal wrinkle: in Australia most Consumer Law guarantees do not apply to goods bought at a traditional auction, where the auctioneer acts as agent for the seller. Misleading-conduct law still applies, so a false description is still actionable, but the automatic guarantees of acceptable quality are not there to catch you. Online marketplaces are generally not traditional auctions in this sense, so guarantees usually do still apply against a business seller trading on them.
Second-hand from a dealer or a consignment store keeps the guarantees, which apply to used goods bought from a business just as to new. Private sales between individuals carry none at all, and that is the honest cost of the good prices you sometimes find there. Buying from a maker directly, through made to order or otherwise, has one advantage worth naming: the person answering your questions is the person who can answer them.

Buying from overseas, and lay-by at home

Overseas online purchases are not automatically cheaper, because the border has arithmetic of its own. Since 1 July 2018 Australia has collected 10 per cent GST at the overseas seller's or marketplace's checkout on imported goods valued at A$1,000 or less, as the Australian Taxation Office sets out. Above A$1,000, GST plus customs duty — commonly 5 per cent on jewellery — plus processing charges are collected at the border by the Australian Border Force before the parcel is released. Run those numbers before concluding a foreign price beats a local one, and add the cost and risk of returning a faulty item across an ocean.
Lay-by, still common in Australian jewellery retail, is regulated and the rules favour you. The ACCC's requirements are that the agreement must be in writing with a copy supplied to you; that you may cancel at any time before delivery and recover all payments made, less only a termination charge that was disclosed up front and is reasonable; and that interest and add-on fees are not permitted. If a store cannot produce a written agreement, that is not a lay-by, it is a handshake with your money in it.

The receipt is the remedy

Australian businesses must provide proof of transaction for purchases over $75 excluding GST, and on request below that; a tax invoice, register receipt, handwritten receipt or lay-by agreement all qualify. Keep it, because it is the trigger document for every remedy you have. Better still, make it a document worth having: the sales paperwork should record metal fineness, finished weight, centre-stone weight stated separately from total carat weight, treatment disclosures, laboratory report numbers, and the after-sale services included — sizing, inspection, re-tipping. That list is close to the question set GIA suggests putting to a jeweller, and asking for it in writing costs nothing but the half-second in which you learn how the seller reacts.
When something fails, the Australian Consumer Law does the work. For consumer purchases from a business, the guarantees of acceptable quality, fitness for purpose and matching description attach automatically, and no store policy can exclude them — no refunds signage on faulty goods is unlawful. For a major failure you choose the remedy, refund, replacement or repair, and the store does not choose for you. The consumer threshold rose from $40,000 to $100,000 on 1 July 2021, and here is the limb most guides miss: goods of a kind ordinarily acquired for personal, domestic or household use are covered at any price. Jewellery is such a good, so a six-figure jewel bought personally keeps its cover. The counterweight is equally plain — the guarantees do not cover change of mind, damage from misuse, or a fault that was pointed out to you before you paid. Your rights are strong on faults and nil on regret.

Valuers, and a word that is not protected

If you need a valuation, know what you are choosing. The National Council of Jewellery Valuers, established in 1984, is Australia's professional body for jewellery valuers and, on its own account, the only Australian jewellery organisation that requires an approved educational standard of its members alongside ongoing professional development and professional indemnity insurance; only members may use the NCJV Registered Valuer mark, and members carry out around two million valuations a year. NSW Government consumer guidance adds the point that matters: choose a valuer who specialises in the type of item, and be aware that NCJV membership is not legally required to practise. Valuer is an unprotected word in Australia. Anyone may use it.
The red flags, then, in the order I meet them: a perpetual was-and-now sale; an in-house certificate offered in place of an independent laboratory report; a valuation waved about as evidence of a bargain; total carat weight quoted with the centre stone withheld; vagueness about whether a chain is hollow; irritation at being asked what backs the melee; and any refusal to put plain facts on the receipt. None is proof of dishonesty on its own; all are reasons to slow down, which costs nothing. Everything we sell is assessed in-house by our FGAA-qualified gemmologist and issued with a Digital Gemstone Passport you can verify independently, with free lifetime re-authentication, because the point of this handbook is that you should never have to take anybody's word for it — including ours.

Questions buyers actually ask

Is jewellery hallmarked in Australia?

No — not in the British sense. Australia has no compulsory hallmarking scheme and no government assay offices, so marking of precious-metal jewellery here is voluntary and almost always applied by the manufacturer itself. The Gold and Silversmiths Guild of Australia, formed in 1988, describes itself as running the only comprehensive voluntary marking scheme in the country, with a kangaroo-head mark and members' maker's marks recorded by impression on fine-silver touchplates held by the Guild. Everything else you see stamped inside a band is the maker's own claim. Your protection is not an assay office but the Australian Consumer Law, which prohibits misleading representations — a real remedy, but one that only helps after something has already gone wrong.

What does the 750 stamp inside my ring actually mean?

750 is a millesimal fineness mark: 750 parts gold per thousand, which is 18 carat. CIBJO's Precious Metals Blue Book recognises 999, 986, 916, 750, 585, 416, 375 and 333, and permits no negative tolerance at all, meaning a piece stamped 750 should assay at 750 or better. In the United Kingdom that figure would sit beside a sponsor's mark and an assay office mark, all three struck after independent testing at one of four assay offices. In Australia it was almost certainly struck by whoever made the piece. The number tells you what the maker asserts; only an assay or an independent test tells you what the metal is.

Is 9ct gold really harder-wearing than 18ct?

This is the most repeated claim in Australian jewellery retail, and the metallurgy does not support it. On the Vickers scale 18ct alloys typically run about 135 to 165 HV against roughly 80 to 120 HV for 9ct, depending on alloy and condition — 18ct is the harder metal. 9ct is 37.5 per cent gold and 62.5 per cent base and white metals, which makes it more brittle, more prone to stress-cracking at solder joints, and quicker to tarnish. The honest resolution is that 9ct scratches marginally shallower while 18ct dents and survives, and that construction quality matters far more than caratage either way.

Can an eternity ring be resized?

A full eternity ring effectively cannot be, because there is no plain metal to cut and rejoin and shortening the band would break the ring of stones. A half-eternity usually takes about one size. A pavé or side-stone shank takes half a size to one size before the beads begin to loosen. A plain solid band takes one to two sizes safely. Tension-set rings cannot be resized at all, because the tension calibration is the setting. Every resize work-hardens the shank, so repeated adjustments weaken it. This is why fit is a pre-purchase decision rather than an after-sales one.

Why is my insurance valuation so much higher than what I paid?

Because it answers a different question. An insurance replacement valuation estimates what it would cost to replace the piece at full retail, at today's metal and stone prices, often through a jeweller who did not sell it to you. It is not an estimate of what you could sell it for: actual resale typically runs 50 to 70 per cent below the retail purchase price. A certificate saying your ring is worth double what you paid is not a windfall, and presenting it as one is a documented sales tactic. This is general information only and not financial product advice — insure at genuine replacement cost, and take valuation questions to a qualified valuer.

Is it safe to buy jewellery online from overseas?

It can be, provided you do the arithmetic first and keep the paperwork afterwards. Since 1 July 2018 Australia has collected 10 per cent GST at the overseas seller's or marketplace's checkout on imported goods valued at A$1,000 or less; above A$1,000, GST plus customs duty — commonly 5 per cent on jewellery — plus processing charges are collected at the border. Consumer guarantees attach to consumer purchases from businesses, and the ACCC's position is that this extends to overseas sellers supplying into Australia — but enforcing a guarantee against a seller with no local presence is far harder in practice than in principle. Get the stone details, metal fineness, treatment disclosures and total carat weight in writing before you pay, not after.

My ring has failed — what are my rights in Australia?

If you bought it as a consumer from a business, the Australian Consumer Law guarantees of acceptable quality, fitness for purpose and matching description attach automatically, and no store policy can exclude them. For a major failure you choose the remedy — refund, replacement or repair — and the store does not. The ACL consumer threshold rose from $40,000 to $100,000 on 1 July 2021, but goods of a kind ordinarily acquired for personal, domestic or household use are covered at any price, and jewellery is such a good, so even a six-figure jewel keeps its cover. The guarantees do not extend to change of mind, damage from misuse, or a fault pointed out to you before purchase. Keep the receipt: Australian businesses must give proof of transaction for purchases over $75 excluding GST, and that document triggers every remedy you have.

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