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Whewellite is an unusual mineral because it is a naturally occurring rare organic substance with a definitive chemical formula. Minerals are traditionally inorganic, but whewellite forms crystals with the aid of oxalic acid from coal or organic debris within sedimentary rocks. This mineral is seldom seen by collectors, and almost never as a faceted gem.

Whewellite Polished
Whewellite Classification
Common Name Whewellite
Species Whewellite
Whewellite Optical Properties
Transparency Transparent - Translucent
Dispersion Strength: None
Refractive Index 1.489-1.651
Birefringence 0.159-0.163
Optic Character Biaxial
Optic Sign Positive
Polariscope Reaction Aggregate (AGG), Doubly Refractive (DR)
Fluorescence SWUV: Inert
LWUV: Inert
Pleochroism Unobservable
Whewellite Characteristic Physical Properties
Hardness 2.5-3
Streak White
Specific Gravity 2.190-2.250
Toughness Poor
Luster Vitreous, Pearly
Fracture Conchoidal
Cleavage Good, in one direction, Poor, in three directions
Whewellite Chemistry & Crystallography
Chemical Name hydrated calcium oxalate
Chemical Formula Ca(C2O4).H2O
Crystal System Monoclinic
Chemistry Classification Organic

Countries of Origin


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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.