With a mysterious sheen reminiscent of moonlight, moonstone has been treasured for thousands of years. This effect, called adularescence, is caused by fine layering of feldspar minerals, which catch the light and shimmer below the gem’s surface. Due to its use as a birthstone for those born on Mondays or as an alternative to pearl and alexandrite for June births, this gem has recently gained popularity. Still, prices are low for all but the top-quality moonstones, and moonstone buying is fairly straightforward. Nevertheless, be wary of simulants and keep in mind the material’s softness when choosing a jewelry setting.

Moonstone Buying and the Four Cs

The IGS moonstone value listing has price guidelines for rainbow moonstone (peristerite), labradorite, white cat’s eye, white adularescent, and other color moonstones.

Color

Moonstone color can be separated into body color and adularescence (sheen) color. Ideally, moonstones exhibit a transparent, colorless body with pure blue, medium-toned sheen.

However, this feldspar can occur in many colors. Any body color detracts from the value, and unattractive green hues will significantly lower the gem’s price. Peach pink hues are popular, but not as highly regarded as colorless stones. Brown, yellow, and blue hues also occur.…