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Carbonate

Mcguinnessite

CuMg(CO₃)(OH)₂
Hardness2.5
Crystal systemMonoclinic
ClassCarbonate
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Mcguinnessite specimen

Mcguinnessite Locality: Premier Chemicals Mine (Gabbs Magnesite-Brucite mine; Basic Refractories mine; Basic mine), Gabbs District, Nye County , Nevada , USA ( Locality at mindat.org ) Blue botryoidal crust of McGuinnessite. Field of view 6 mm. Specimen and photo Leon Hupperichs. — Photo: Leon Hupperichs · CC BY-SA 3.0

Mcguinnessite

Mcguinnessite is an IMA-recognized mineral species in the carbonate class, with the chemical formula CuMg(CO₃)(OH)₂.

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

Key properties: Mohs hardness 2.5; specific gravity 3.02–3.22; Vitreous to silky luster; optically biaxial.

IMA symbol Mgu, IMA status: approved, named in 1977.

A rare secondary mineral, typically formed in serpentinized peridotite.

It is found associated with Vuagnatite, malachite, azurite, chrysocolla, iron oxides (Red Mountain, California, USA); coalingite, pokrovskite (Cedar Hill quarry, Pennsylvania, USA).

The mineral was named to honor Albert Leo McGuinness (1926–1990), amateur mineral collector and dealer, San Mateo, California, USA, for his contributions to scientific mineralogy.

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.