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Arsenate

Molybdofornacite

CuPb₂(MoO₄)(AsO₄)(OH)
Hardness3–4
Crystal systemMonoclinic
ClassArsenate
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Molybdofornacite specimen

Molybdofornacite Locality: Tsumeb Mine (Tsumcorp Mine), Tsumeb , Otjikoto (Oshikoto) Region, Namibia ( Locality at mindat.org ) Picture width 1 mm. Collection and photograph Christian Rewitzer — Photo: Christian Rewitzer · CC BY-SA 3.0

Molybdofornacite

Molybdofornacite is an IMA-recognized mineral species in the arsenate class, with the chemical formula CuPb₂(MoO₄)(AsO₄)(OH).

It crystallizes in the monoclinic crystal system (space group P2_1/c). It is a member of the Fornacite structural group.

Key properties: Mohs hardness 3–4; specific gravity 6.6; Pale yellow streak; Adamantine luster; optically biaxial.

IMA symbol Mfor, IMA status: approved, named in 1982.

Found in the deep oxidation zone of a dolostone-hosted hydrothermal polymetallic ore deposit (Tsumeb, Namibia).

It is found associated with Dioptase, duftite, wulfenite, quartz, calcite, hematite (Tsumeb, Namibia); wulfenite, pyromorphite (Tonopah-Belmont mine, Arizona, USA); mimetite, descloizite.

The name refers to its predominance of molybdenum and relation to fornacite.

Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet. Browse more M minerals or help write this entry.