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Formula: Pb2Mn3+2O2(Si2O7)
Sorosilicate (Si2O7 groups),
manganese-bearing mineral, forms a series with
melanotekite
Crystal System: Orthorhombic
Specific gravity: 6.26 measured, 6.29 calculated
Hardness: 5
Streak: Brown to yellowish brown
Colour: Black, sometimes with dark red internal reflections
Common impurities: Ti,Al,Fe,Zn,Mg
Environments:
Kentrolite occurs in oxide zinc deposits (Mindat).
Localities
At the type locality in Chile (not specified in any more detail) kentrolite is associated
with quartz, baryte
and apatite
(HOM).
At the Ushkatyn deposits, Karazhal, Karaganda Region, Kazakhstan, kentrolite occurs
in veinlets cutting franklinite ore in bedded
manganese deposits. Associated minerals include
garnet, tephroite,
franklinite and
braunite
(HOM).
At the Långban Ore District, Filipstad, Värmland County, Sweden, kentrolite is associated
with braunite, richterite
and baryte
(HOM).
At the Franklin mine, Franklin, Franklin Mining District, Sussex County, New Jersey, USA,
kentrolite occurs in a cavity in calcite in a
metamorphosed stratiform zinc deposit.
Associated minerals include calcite,
willemite and
franklinite.
(HOM).
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