Minium

minium

massicot

cerussite

galena

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Formula: Pb2+2Pb4+O4
Multiple oxide
Specific gravity: 9.05
Hardness: 2½
Streak: Orange-yellow
Colour: Red to brownish red
Solubility: Soluble in hydrochloric acid with evolution of Cl2. Decomposed by nitric acid, with brown residue of PbO2
Environments:

Metamorphic environments

Minium occurs in the oxidised portions of lead ore deposits (Webmin), formed under extreme oxidising conditions (R&M 91.1.33).

Localities

At the Nakhlak Mine, Anarak District, Nain County, Isfahan Province, Iran, epigenetic (formed later than the surrounding or underlying rock formation) vein deposits and metasomatic replacement bodies are hosted by a chalky Upper Cretaceous (100.5 to 66 million years ago) limestone. The limestone underwent dolomitisation prior to sulphide mineralisation. The principal primary ore mineral is galena, associated with minor or trace amounts of sphalerite, tetrahedrite -tennantite, pyrite and chalcopyrite as inclusions. The main secondary ore mineral is cerussite, sometimes associated with minor amounts of anglesite, plattnerite, wulfenite, minium, mimetite, covellite, chalcanthite, malachite and goethite. Many trace elements are present in the primary galena, but most notably it is rich in silver and antimony and poor in bismuth.
Minium occurs rarely as orange botryoidal layers in the supergene zone (Minrec 54.3.383-408).

At the Santa Fé mine, Bolaños, Mun. de Bolaños, Jalisco, Mexico, minium is associated with massicot and cerussite (Dana).

At the Berg Aukas mine, Grootfontein, Otjozondjupa Region, Namibia, minium has been found forming red encrustations on coarse-grained galena (R&M 96.2.132).

At the Långban mine, Långban Ore District, Filipstad, Värmland County, Sweden, minium is associated with native lead (Dana).

At Leadville, Lake county, Colorado, USA, minium is associated with galena, cerussite and iron oxides (Dana).

At the Jay Gould Mine, Wood River Mining District, Blaine county, Idaho, USA, minium is associated with native lead and galena (Dana).

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