Moonstone is quite a remarkable stone, exhibiting a distinctive visual effect unlike any other. As you turn it in your hand, an ethereal sheen skips across the surface. This sheen may even appear to glow, often with a ghostly blue hue.

Classifying moonstone is actually a bit complicated. Moonstone may be any of several different members of the feldspar group, most commonly orthoclase, oligoclase, or microcline. Moonstone actually comes in a wide variety of colors, however. Along with the white and colorless specimens, you can find moonstone which is blue, green, orange, pink, brown, purple, gray, or yellow. On the Mohs scale of hardness, moonstone is a 6, which positions it between apatite (5) and quartz (7).

The visual effect which gives moonstone its name is the result of the gem’s microstructure. Moonstone consists of a number of feldspar layers. This layering causes the light to diffract, resulting in the appearance of a mysterious “moonbeam” which floats across the gem as you turn it. This effect is known as “adularescence.”

Along with adularescence, moonstone may also exhibit a few other visual effects. One is a cat’s eye effect where a band of light appears to hover over the stone as you move it. The other is asterism. Asterism is the appearance of a “star” on the surface of the stone, such as you see with star sapphire. Asterism is not as common as adularescence and the cat’s eye effect.

You might think that moonstone would be expensive, but it is actually quite reasonably priced. The more transparent a specimen is and the more pronounced the adularescence is, the more you will pay. Because moonstone is relatively common and inexpensive, you will find it used in numerous jewelry creations. Larger pieces may be used to make pendants or brooches, while smaller pieces may be used in the creation of rings or earrings. Moonstone beads for necklaces and bracelets are also very popular.

As moonstone is such a distinctive gemstone, it has quite a rich history. It is easy for historians and archaeologists to trace its use back to ancient times. Many cultures around the world prized moonstone and believed that it possessed mystical qualities. Ancient Romans, Greeks, and Indians believed that moonstone was quite literally composed of solidified moonbeams.

For this reason, moonstone was closely associated with the lunar gods of the ancient Greeks and Romans. Many believed that it was a lucky stone to carry.