June babies have a lovely trio of birthstones. Pearl, Alexandrite, and Moonstone. Moonstone is probably the best known of the feldspar group of gemstones. Feldspars are the most widespread minerals in the earth’s crust, as well as some of the most diverse. You can pick up a rock anywhere in the world, and you’ll probably find that it contains a mineral or two from the feldspar group.
Regardless of feldspar being widespread, there are gorgeous gem quality stones in this group. Moonstone, Amazonite, Andesine, Labradorite, and Sunstone. Feldspar is also what gives granite its pink, grey, and green colors. The colors all come about because of the impurities in the crystals.
In moonstone, orthoclase and albite are mixed and then as the newly formed mineral cools, they separate into alternating thin layers and as the light falls between the layers and scatters producing the phenomenon known as adularescence. Adularescence is the light that appears to billow across the gemstone giving a ghostly appearance. This light seems to roll across the gemstone when observed from different angles. There are other stones that have this adularescence, Labradorite from Canada and Labrador. Another labradorite from Madagascar id the multi-color adularescence over a light body color. It is called a rainbow moonstone but it is really a Labradorite. Regardless of the identity of the stone, what is important is the beauty of the adularescence.
With Moonstone, a blue sheen over a colorless background is a prized stone. This is seen in the picture below courtesy of Temple Trading Company. According to Hindu mythology, moonstone is made of solidified moonbeams. Many other cultures also associate this gem with moonlight, and it’s easy to see why. Its internal structure scatters the light that strikes it. The visual effect is reminiscent of the full moon shining through a veil of thin, high clouds.
Many say moonstone brings good luck and if you held a moonstone in your mouth during a full moon, you could see the future. Adularescent moonstone was once called “adularia.” The name originated with a city in Switzerland, Mt. Adular (now St. Gotthard), that was one of the first sources of fine-quality moonstone. This comes as a surprise to many.
Moonstone can also have the cats- eye effect and is rare in top qualities. This stone has been confused with the mood ring, and they could not possibly be more separate, with the mood stone not a quality gemstone at all.