Harkerite

harkerite

monticellite

vesuvianite

cuspidine

Images

Formula: Ca12Mg4Al(CO3)5(BO3)3(SiO4)4.H2O
Compound carbonate, forms a solid solution with sakhaite
Specific gravity: 2.96
Streak: White
Colour: White, tannish brown
Solubility: Dissolves with effervescence in acetic or hydrochloric acid
Common impurities: TR,Ce,Fe,Mn,Sr,F,Cl
Environments

Volcanic igneous environments
Metamorphic environments

Harkerite is a high-temperature mineral that occurs in skarn in dolomitic limestone at the contact with granite (Webmin, Mindat). Associated minerals include calcite, chalcocite, monticellite, diopside, magnetite, vesuvianite, cuspidine and phlogopite (HOM, Mindat).

Localities

At the Alban Hills, Metropolitan City of Rome Capital, Lazio, Italy, harkerite occurs in volcanic ejecta (HOM).

At the type locality, Camas Malag, Torrin, Broadford, Isle of Skye, Eilean á Chèo, Highland, Scotland, UK, harkerite occurs in skarn containing monticellite and calcite, and accessory bornite, chalcocite, magnetite and diopside, at the contact of dolomitic limestone with granite (AM 37.359). The harkerite is associated very intimately with calcite, which is a product of its alteration (AM 62.263-272).

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