Melanotekite

melanotekite

magnetoplumbite

plumboferrite

lead

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Formula: Pb2Fe3+2O2(Si2O7)
Sorosilicate (Si2O7 groups)
Crystal System: Orthorhombic
Specific gravity: 5.73 to 6.28 measured, 6.30 calculated
Hardness: 6½
Streak: Greenish
Colour: Grey, black
Solubility: Decomposed by nitric acid
Common impurities: Ti,Al,Mn,Mg
Environments:

Pegmatites
Metamorphic environments

Localities

At the type locality, the Långban mine, Långban Ore District, Filipstad, Värmland County, Sweden, melanotekite occurs with native lead in a metamorphosed iron-manganese deposit (HOM).

At Dara-i-Pioz, Districts of Republican Subordination, Tajikistan, melanotekite occurs in an aluminium-poor, sodium and potassium-rich pegmatite (Dana).

At Artillery Peak, Artillery Mountains, Mohave County, Arizona, USA, melanotekite is found in oxidised lead-copper ores (HOM).

Alteration

At 650oC, melanotekite can coexist with quartz, hematite, magnetoplumbite and plumboferrite (AM 52.1085).

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