Whewellite
Whewellite
Published: June 2014
Modified: November 2021
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.
General Information
Common Name
Whewellite
Species
Whewellite
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
LWUV: Inert
Pleochroism
Unobservable
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
Chemical Name
hydrated calcium oxalate
Chemical Formula
Ca(C2O4).H2O
Crystal System
Monoclinic
Chemistry Classification
Organic
Whewellite Colors
-
Brown -
Yellow -
White -
Colorless
Countries of Origin
Unknown; Czechia