Shown above: Carved Moonstone from the National Gem Collection
Moonstones are beautiful gems from the Earth. During the summer while researching gemstones for a custom design project, I came across some interesting gemstone facts from AGTA, the American Gem Trade Association.
The ancient Romans theorized that moonstone, with its unearthly shimmer, was formed from frozen moonlight.
Moonstones come in a variety of colors. The body color can range from colorless to gray, brown, yellow, green, or pink. The clarity ranges from transparent to translucent. The best moonstone has a blue sheen, perfect clarity, and a colorless body color.
Sometimes moonstone will have an eye as well as sheen. Another related feldspar variety is known as rainbow moonstone. In this variety of labradorite feldspar, the sheen is a variety of rainbow hues, from pink to yellow, to peach, purple, and blue.
Fine moonstone is quite rare and becoming rarer. It is mined in Sri Lanka and Southern India. The rainbow variety can be found in India and Madagascar.
Moonstones are usually cut in a smooth-domed oval cabochon shape to maximize the effect. Sometimes they are carved to show a man-in-the-moon face. Personally, I like to use fin shaped cut moonstones shown in the picture below.
Moonstone has a hardness of 6 to 6.5. It should be stored in its own gem bag to prevent scratching. Clean with mild dish soap: use a toothbrush to scrub behind the stone where dust can collect.