Henritermierite

henritermierite

marokite

hausmannite

gaudefroyite

Images

Formula: Ca3Mn3+2(SiO4)2(OH)4
Nesosilicate (insular SiO4 groups), henritermierite group, garnet supergroup, manganese-bearing mineral
Crystal System: Tetragonal
Specific gravity: 3.34 measured, 3.40 calculated
Streak: White
Colour: Clove-brown to apricot-brown; lemon-yellow to pale yellow in thin section.
Solubility: Slowly dissolved by cold hydrochloric acid, easily by warm hydrochloric acid, leaving a silica residue. Nitric acid attacks henritermierite superficially with formation of black MnO2 (AM 54.1739)
Common impurities: Fe
Environments

Metamorphic environments

Localities

At the type locality, the Tachgagalt mine, Tansifite Caïdat, Agdz Cercle, Zagora Province, Drâa-Tafilalet Region, Morocco, henritermierite occurs in the manganese ore deposit in aggregates of small grains up to 0.5 mm; mostly about 0.2 mm across. The grains fill interstices between crystals of marokite, hausmannite, and rare gaudefroyite. Calcite is commonly present also (AM 54.1739).

At the N'Chwaning Mines, Kuruman, Kalahari manganese field, Northern Cape, South Africa, henritermierite is associated with hausmannite, manganite, hematite, calcite, baryte and andradite (HOM).

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