Why are Moonstones called…Moonstones?

A lot of cultures associate this gem with moonlight, and it's very easy to understand why. Its internal composition disperses the light that hits it and generates a process known as adularescence. The visual effect is reminiscent of the full moon shining through a curtain of high, thin clouds.

Legends believe moonstone brings good luck. Many cultures also claimed that if you placed a moonstone in your mouth during a full moon, you would predict the future. Moonstones range from semi-transparent to opaque. Most of the time, you'll see them in cabochons and carvings, set in rings and pendants.

You should know that moonstones are feldspar gemstones with varying compositions. Usually, they are orthoclase feldspars with alternating orthoclase and albite layers. Now that we have reminded you of this, we will explain why they showcase such a singular phenomenon called adularescence.

Adularescence is caused by light diffraction when it impacts small, alternating layers of orthoclase and albite within the gem. This gives the appearance of a swirling, blue to white light cloud-like, within the gem.

In orthoclastic moonstones, a blue glow is produced when the albite crystals are very fine. Fine albite crystals are orthoclase and albite plates that are scattered within each other as a result of cooling unmixing during their formation. In other words, if the albite plates are thick, the light will be white.

With more than a decade of marketing experience, I am now based in Bangkok where I combine my professional background with a long-standing passion for gemstones. I write articles that explore both the beauty and the business of gems, offering insights into their history, trade, and market dynamics. My goal is to make the world of gemstones more accessible to anyone curious to learn, while bringing in the perspective of someone who understands both storytelling and strategy.