Moonstone is a member of the feldspars, the most abundant mineral group in the Earth's crust. The stone is famous for its pearly blue opalescence and bronzy iridescent luster.

Class: semiprecious
Origin of Name: named for its pearly luster, reminiscent of the Moon
Color: colorless, white to yellowish grey, reddish to bluish grey
Chemical Composition: potassium aluminum silicate
Crystal System: monoclinic
Hardness: 6
Specific Gravity: 2.56-2.59
Geographic Origins: Sri Lanka, India, Madagascar, Burma, Tanzania, Colorado, Indiana, New Mexico, New York, North Carolina, Pennsylvania, Virginia, Wisconsin


Photo: ©International Colored Gemstone Association/Bart Curren

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