simpsonite
simpsonite crystal from Rio Grande do Norte in Brazil
Detailed sheet
simpsonite
It was discovered in Australia and its name honors the Australian mineralogist Edward Sydney Simpson (1875-1939).
CHEMICAL CHARACTERISTICS
Al4(Ta,Nb)3O13(OH)
aluminum oxide and rare earth
PHYSICAL CHARACTERISTICS
Main color
orange
Other colors
white, brown, yellow
Color of streak
white
Luster
adamantine, resinous
Hardness
7.0 to 7.5
Density
5.90 to 6.85
Cleavage
none
Fracture
conchoidal
OPTICAL PROPERTIES
Transparency
translucent
Refractive index
1.990 - 2.040
Double refraction
0.020
definite negative uniaxial
visible double refraction
No
Pleochroism
absent
Number of colors
1
Fluorescence
variable
blue, yellow
CRYSTALS PROPERTIES
rarely well shaped
crystals system
trigonal
OTHER INFORMATIONS
APPROACHING GEMS
Exploited
sites
It is found in Brazil (Vulture Mine), in pénisule Kola in Russia, Australia.
use in jewelry
It’s a collection stone
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Gems
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