Moonstone

Moonstone in antiquity was covered in mythology: in India it was believed to be formed from solidified moonbeams and to have the power of prophecy — during a full moon it was placed in the mouth to reveal the future. Romans believed it was made from congealed moonlight.

In Western Europe, moonstone became popular in the Art Nouveau era (1890–1910) — René Lalique and other Art Nouveau jewelry masters frequently incorporated it into organic, feminine designs alongside enamel and pearl.

Moonstone became a symbol of love and romance in the 19th century and is traditionally gifted for the twenty-third wedding anniversary. In astrology it is associated with the Moon sign and Cancer.

Adularescence: The phenomenon arises from a microscopic lamellar structure — alternating layers of orthoclase and albite feldspar, only 10–100 nm thick. Light scatters at the layer boundaries, creating a diffuse bluish glow that floats above the stone. Ceylon moonstones have the most intense blue sheen — called "blue moon."

Blue vs. white sheen: Blue sheen is premium (Ceylon, Burma). White or milky sheen is typical for most Indian moonstones. Sheen color depends on lamella thickness — thinner → blue; thicker → white.

Rainbow moonstone: The name is slightly misleading — "rainbow moonstone" is actually labradorite (a plagioclase feldspar variety, not orthoclase), with multicolored labradorescence instead of adularescence. Highly prized but gemologically a different mineral.

Cat's eye moonstone: Rare specimens show asterism (cat's eye) — a linear light band instead of floating glow. Cut as cabochon.

Indian moonstone: Rajasthan, India, is the largest source. Yellowish-orange body with white sheen — typical "peach moonstone." Lower value compared to Ceylon.

Symbolism: In ancient Greece and Rome, moonstone was associated with Selene/Luna goddess. In India it is a sacred stone. Art Nouveau jewelry (late 19th c.) was obsessed with moonstones — René Lalique set moonstones in iconic pieces.

High-quality moonstone with intense blue adularescence ("blue moon") from Sri Lanka is one of the most sought-after and increasingly rare stones. Ceylon moonstones with a clear, colorless body and vivid floating blue light are premium — deposits are diminishing.

Moonstone belongs to the feldspar group — the most common mineral group in the Earth's crust. Despite this, high-quality adularescent stones are rare because they require a specific orientation of adularia/albite lamellae to create the interference effect.

The Indian deposit (Rajasthan) yields colorful moonstones with pink, orange, and green body color that have become a popular alternative to Ceylon stones in the past 20 years.

Adularescence is created by the interference of light on alternating layers of two feldspar types — orthoclase and albite. When light enters the stone, it refracts at the lamellar boundary and creates a floating, moving light point. The dome height of the cabochon directly affects the intensity of the phenomenon.

"Centipede" inclusions (centipede inclusions) are micro-fractures along cleavage planes characteristic of moonstone — per GIA they are visible only in cabochon. They are an aesthetic minus but a sign of naturalness.

Moonstone is the official state gemstone of Florida, USA — in honor of the Apollo missions (moon missions) that launched from Florida in the 1960s and 1970s.