colemanite
colemanite crystals from Turkey
colemanite crystals from Turkey
Detailed sheet
colemanite
It pays tribute to W. Coleman (1824-1893), founder of the borax industry in California.
CHEMICAL CHARACTERISTICS
Ca[B3O4](OH)3 H2O
hidrated calcium borate
PHYSICAL CHARACTERISTICS
Main color
colourless
Other colors
white, grey, yellow
Color of streak
white
Luster
vitreous
Hardness
4.5 to 0.0
Density
2.40 to 2.42
Cleavage
perfect
Fracture
conchoidal
OPTICAL PROPERTIES
Transparency
translucent, transparent
Refractive index
1.586 - 1.615
Double refraction
0.028
weak, biaxial (+)
visible double refraction
Yes
Dispersion
faible
Pleochroism
absent
Number of colors
1
Fluorescence
weak
yellow
CRYSTALS PROPERTIES
short prismatic and often flattened
crystals system
monoclinic
OTHER INFORMATIONS
APPROACHING GEMS
Exploited
sites
It is found mainly in desert areas or borax deposits were they get formed.
The death valley in the United States, Bolivia, Argentina, Kazakhstan, Turkey, Iran.
use in jewelry
it is faceted for collection
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