Moonstone, a Mineral of the Moon?

     Moonstone’s name might suggest that it's of a lunar origin, but moonstone is from the earth. Moonstone is actually a type of feldspar that is named for its sheen, which reminds some people of the moonlight.
     Moonstone is a variety of feldspar that is named for its adularescence. Adularescence is the term for the type of sheen that moonstone exhibits, which resembles moonlight. Moonstone is orthoclase feldspar with alternating layers of albite feldspar in it. The way in which these layers reflect the sunlight is what gives moonstone its sheen. The sheen can be either blue or white depending on the layers inside of the moonstone. If the layers of albite are thin then the moonstone’s sheen is blue. If they are thick then the sheen is white. Moonstone itself is usually colorless, white, or a light shade of blue-gray, but it can also be orange, blue, yellow, brown, or green. Moonstone’s crystals are monoclinic, but I have personally never seen whole moonstone crystals (all of my samples appear to be broken pieces) so I can't describe their appearance. Moonstone’s transparency ranges from almost transparent to almost opaque.
      Moonstone serves some use as a gemstone because its moonlike sheen is very desirable. The best moonstone comes from Sri Lanka and Myanmar. Other sources include: India, Madagascar, Tanzania, Brazil, Mexico, the United States, and the European Alps.
     Moonstone possesses some rare qualities among minerals. Its moonlike sheen is, as far as I know, unique to moonstone. Moonstone may be a lot of things, but just remember, it’s not from the Moon!