Rickturnerite

rickturnerite

mereheadite

cerussite

plumbonacrite

Images

Formula: Pb7O4[Mg(OH)4](OH)Cl3
Hydroxyhalide
Crystal System: Orthorhombic
Specific gravity: 6.886 calculated
Hardness: About 3
Streak: White
Colour: White to pale green
Environments

Hydrothermal environments

Rickturnerite is a relatively new mineral, approved in 2010.

Localities

At the Kombat Mine, Kombat, Grootfontein, Otjozondjupa Region, Namibia, a specimen purportedly from Tsumeb but more likely from the Kombat mine was identified as parkinsonite, with a fibrous white phase that appeared to be rickturnerite JRS 13.30).

At the Wesley Mine, Westbury on Trym, Bristol, England, UK, yellowish grey rickturnerite was found. The colour appears to be due to the decomposition of rickturnerite and is presumably caused by a coating of leadoxide or carbonate (JRS 13.30).

At the type locality, the Torr Works Quarry, Cranmore, Mendip, Somerset, England, UK, rickturnerite occurs as pale emerald green to grey porous aggregates of disordered interwoven minute fibrous crystals with mereheadite, cerussite, calcite, aragonite, mimetite, hydrocerussite, plumbonacrite and an uncharacterised lead oxychloride, in cavities inside a manganite and pyrolusite pod in limestone. The crystals are typically less than 5 μm wide and 200 μm long, but they can reach 40×100 μm in cross-section and over 1 mm in length. The green colouration is due to a small amount of copper replacing magnesium; when pure, the mineral is whitish grey (MM 76.59-73, JRS 13.30).

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