pyrolusite
pyrolusite from Platten
Detailed sheet
pyrolusite
Identified and named in 1827, its name comes from the Greek words meaning “fire” and “who washes”, as it was used to remove from glass its green and brown color due to iron.
This is the main element of “dendrites ” black seepage into the stone looking like ferns (Solnhofen in Germany).
CHEMICAL CHARACTERISTICS
MnO2
manganese dioxide
PHYSICAL CHARACTERISTICS
Main color
black
Other colors
blue, grey
always very dark, black with sometimes bluish reflections
Color of streak
blue, black
Luster
greasy, metallic
Hardness
6.0 to 7.0
Density
4.50 to 5.00
Cleavage
perfect
Fracture
uneven
OPTICAL PROPERTIES
Transparency
opaque
Refractive index
0.000 - 0.000
Double refraction
0.000
refractive index unreadable and no birefringence
visible double refraction
No
Dispersion
-
Pleochroism
very weak
Number of colors
1
yellow variants practically unobservable
Fluorescence
none
CRYSTALS PROPERTIES
very rare, in botryoidal aggregates glistening, radiant structure on the break
crystals system
tetragonal
OTHER INFORMATIONS
APPROACHING GEMS
Exploited
sites
This is a major manganese ore, it is found worldwide. Deposits in Africa, Gabon, Ghana, Namibia, South Africa, Cambodia, England, Germany, Greece …
use in jewelry
it is cut cabochon and used like other black stones.
Other
Gems
Venez visitez
notre site web
voillot-joaillier.fr
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