Whewellite Gem Guide and Properties Chart

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

Classification
Optical Properties
Characteristic Physical Properties
Chemistry & Crystallography

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

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