Schoenfliesite

schoenfliesite

berborite

hulsite

cassiterite

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Formula: MgSn(OH)6
Hydroxide, schoenfliesite subgroup, forms a series with wickmanite, tin-bearing mineral
Specific gravity: 3.32
Hardness: 4 to 4½
Streak: Nearly white, lighter than massive mineral
Colour: Dark red-brown, yellow, orange, greenish yellow
Solubility: Soluble in hydrochloric acid and slowly soluble in NaOH and in NH4OH
Environments

Metamorphic environments
Hydrothermal environments

Schoenfliesite occurs in serpentinised dolostone in contact with boron-beryllium-strontium-tungsten skarn. Associated minerals include berborite, calcite, cassiterite, chondrodite, diopside, dolomite, fluorite and magnetite (Mindat).

Localities

At Lake Ladoga, Republic of Karelia, Russia, schoenfliesite occurs in chlorite-serpentine rock, associated with chondrodite, diopside, fluorite, calcite, dolomite and magnetite (Dana).

At the Pitkyaranta mining district, Ladoga Region, Republic of Karelia, Russia, schoenfliesite occurs as a low temperature mineral in serpentinised dolostone associated with boron-beryllium-strontium-tungsten skarn. It has been found in lumps of chlorite-serpentine rock from a mine dump. This rock commonly contains relicts of chondrodite and diopside, as well as grains, lenses, and small veins of fluorite, calcite, dolomite and magnetite. Spread in this matrix are small groups of prismatic crystals of cassiterite from a few mm to 7 cm long. The cassiterite is often covered with a fibrous crust of schoenfliesite, from 0.01-0.15 mm thick; the schoenfliesite is overgrown by a crust of calcite or fluorite, or by fluorite and then calcite. Associated minerals include cassiterite, berborite, calcite, fluorite, dolomite, magnetite, chondrodite and diopside (CM 15.437-445, HOM).

At the type locality, Brooks Mountain, Seward Peninsula, Nome Census Area, Alaska, USA, schoenfliesite is a late-stage hydrothermal alteration product of hulsite in a boron-metasomatised limestone near the contact with a granite intrusive. Associated minerals include maghemite, hulsite, goethite, magnetite, fluorite and hematite (HOM, Dana, Mindat).

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