Some gems sparkle; moonstone breathes. Tilt a fine one and a soft blue light billows across its surface like moonlight through cloud — a phenomenon with the beautiful name adularescence, and the reason this modest feldspar has enchanted jewellers for two thousand years.
How the glow works
Moonstone is built from microscopically thin alternating layers of two feldspars; light entering the stone scatters between them and emerges as that floating sheen. Thinner layers make blue light; thicker layers make white. It is the same physics-as-poetry family as opal's play-of-colour and the star sapphire's rays: inclusions and structure creating magic.
What fine means
The benchmark: a near-transparent body with a strong, centred blue sheen that glides as the stone moves. Ceylon has historically produced the finest — one more entry in Sri Lanka's gem ledger — and fine blue-sheen material has grown genuinely scarce, with prices to match. Milky stones with weak sheen are charming and cheap; know which you are buying. ('Rainbow moonstone', by the way, is technically a labradorite cousin — lovely, but label-honesty matters.)
The romantic résumé
June's alternative birthstone (sharing the month with pearl), sacred to moon deities from Rome to India, and the signature stone of Art Nouveau's dreamers — René Lalique set it constantly (see style periods).
Honest care talk
Mohs 6–6.5 with cleavage planes: moonstone is a gem for pendants, earrings and occasional-wear rings, not the gym. Warm soapy water only; protect from knocks; let settings shelter the stone (bezels are its friend). Fragility is the tax on ethereal.
A cabochon moonstone glowing against dark metal is among the most quietly beautiful things our bench produces — commission one or ask what's in the vault.
Continue your gem education
Pearls: A Complete Guide · Birthstones by Month · Star Sapphires & Asterism · browse all Gem Guides — or explore fine jewellery.