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Moonstone is a variety of feldspar that displays an amazing optical phenomenon called, adularescence. Internallyrepeating feldspar layers scatter the light that enters the stone creating a mystical glow reminiscent of moonbeams.This glow comes to life, rolling across the gems surface, when it is moved. Adularescent labradorite with a multi-colored glow is sometimes called Rainbow Moonstone.

Moonstone Rough
Moonstone Classification
Common Name Moonstone
Species Feldspar
Moonstone Optical Properties
Transparency Transparent - Translucent
Refractive Index 1.559-1.568
Birefringence 0.005-0.011
Optic Character Biaxial
Optic Sign Positive
Polariscope Reaction Doubly Refractive (DR)
Fluorescence SWUV: weak pinkish orange
LWUV: moderate chalky blue
Pleochroism Unobservable
Moonstone Characteristic Physical Properties
Hardness 6-6.5
Streak White
Specific Gravity 2.650-2.750 Range:+/-0.05 Typical:2.690
Toughness Poor
Inclusions Moonstone occasionally contains colorless inclusions and might show parallel multiple twinning planes.
Luster Vitreous
Fracture Uneven, Splintery
Cleavage Perfect, in two directions
Moonstone Chemistry & Crystallography
Chemical Name calcium, sodium aluminum silicate
Chemical Formula NaAlSi3O8 and CaAl2Si2O8
Crystal System Triclinic
Chemistry Classification Silicate

Moonstone Colors

  • Brown Moonstone Brown
  • Red Moonstone Red
  • Gray Moonstone Gray
  • Pink Moonstone Pink
  • Orange Moonstone Orange

Alternate Names

Rainbow Moonstone, Star Moonstone

Countries of Origin

Tanzania, United Republic Of; Myanmar; United States of America (the); Sri Lanka; Madagascar; Switzerland; French Polynesia; India; Mozambique; Unknown; China; Russian Federation (the); Brazil

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Tim Matthews


Tim Matthews

Tim Matthews is President and Chief Executive Officer of Jewelry Television® (JTV), as well as a member of the company's Board of Directors. He oversees and leads all aspects of the company's powerful omni-digital retail platform that uniquely specializes in fine jewelry and gemstones. His passion for business and gemstones has led him to become a recognized expert in the field of gemology. He is a life member of the Gemmological Association of Great Britain (Gem-A) and has earned Gem-A's highest degrees, the Gemmology (FGA) and Diamond (DGA) diplomas. He is also a Graduate Gemologist (GG) of the Gemological Institute of America (GIA) and has also completed GIA's Graduate Diplomas in Diamonds, Colored Stones and Pearls. Under his leadership, JTV has become the leader in the sourcing and selling of color gemstones and jewelry.

This page was created on June 27, 2014.

This page was last edited on October 24, 2019.