Dioptase
Dioptase
Published: June 2014
Modified: October 2021
Dioptase is a bright emerald-green or blue-green gemstone noted for the visibility of internal cleavage planes. The transparent to translucent dioptase gemstone is uncommon and generally found in desert regions. Rivaling the beauty of emerald, dioptase is typically sold as specimens and gemstones are rarely seen, especially in sizes over 1 carat.
General Information
Common Name
Dioptase
Species
Dioptase
Transparency
Transparent - Translucent
Dispersion
Strength: Moderate Fire Value: 0.036
Refractive Index
1.644-1.709
Tolerance:(+0.012/-0.012)
Tolerance:(+0.012/-0.012)
Birefringence
0.051-0.053
Optic Character
Uniaxial
Optic Sign
Positive
Polariscope Reaction
Doubly Refractive (DR)
Fluorescence
SWUV: inert
LWUV: inert
LWUV: inert
Pleochroism
Dichroic, unobservable or weak, varying shades of body color
Hardness
5
Streak
Greenish
Specific Gravity
3.280-3.350 Typical:3.300
Toughness
Poor
Luster
Vitreous
Fracture
Conchoidal, Uneven
Cleavage
Perfect, in one direction
Chemical Formula
CuSiO2(OH)2
Crystal System
Trigonal
Chemistry Classification
Silicate
Dioptase Colors
-
Green
Countries of Origin
Unknown; Namibia; United States of America; Brazil; Kazakhstan; Congo