Moonstone

 

Moonstone Rock Professor Image
MOONSTONE, or adularia, is a potassium feldspar of the orthoclase species. It is composed of two feldspar minerals, orthoclase and albite. Moonstone is prized as a gemstone because of its silvery or blue shimmer called adularescence, which is due to diffraction of light as it hits thin, alternating layers of orthoclase and albite within the gem.
 
Group : Orthoclase Feldspar ♦ Variety: moonstone ♦ Crystal Form: Monoclinic ♦ Moh's Hardness: 6.0 ♦ Chemstry: Sodium Potassium Aluminium Silicate ♦ Luster: Vitreous, pearly ♦ Fracture: Uneven to Conchoidal ♦ Color: Grey, white, pink, green, brown, deep blue ♦ Localities: Sri Lanka, Burma, Brazil, India, Madagascar, USA