Why are Moonstones called…Moonstones?

A lot of cultures associate this gem with moonlight, and it's very easy to understand why.
Easy

Post difficulty
3 min

Post Length
Science

Gem-related Field

corundum
Moonstones Are Full Of Legends
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.
Moonstones are available at GemMatrix for specific requests only.
THE QUESTION
What is the Adularescence Effect?
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.

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Benjamin Poudevigne
Social Media Manager at GemMatrix
With over ten years of marketing experience, I finally decided to settle down in Bangkok to work in an area that I have always been interested in: the gemstones industry. I'm still learning how the market works on a daily basis, and I enjoy sharing my experience with those who are interested in learning more about gems in general.