Images
Formula: (Mg,Mn)2(Mn3+,Sb5+)O2(BO3)
Anhydrous monoborate,
pinakiolite group, monoclinic
paramorph of orthorhombic
orthopinakiolite
Crystal System: Monoclinic
Specific gravity: 3.88 measured, 3.94 calculated
Hardness: 6
Streak: Brown-grey
Colour: Black; deep reddish brown in transmitted light
Solubility: Soluble in concentrated hydrochloric acid with the evolution of poisonous elemental chlorine
Environments
Localities
At the type locality, the Långban Mine, Långban Ore District, Filipstad, Värmland County, Sweden, pinakiolite
occurs as a rare mineral in banded granular dolomite in a metamorphosed
iron-manganese orebody, associated
with hausmannite, tephroite,
berzeliite, manganophyllite,
dolomite and calcite
(HOM).
Pinakiolite from Långban - Image
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