Plumbogummite

phosphate

lead

Formula: PbAl3(PO4)(PO3OH)(OH)6
Hydrated phosphate containing hydroxyl, crandallite group
Specific gravity: 4.01
Hardness: 4½ to 5
Streak: White
Colour: Light blue, grey-white, yellow-grey, yellow, yellow-brown, red-brown, greenish, bluish, dark blue-grey
Solubility: Soluble in hot acids
Environments:

Hydrothermal environments

Plumbogummite is a relatively common secondary mineral in the oxidised zone of lead deposits often associated with pyromorphite and baryte, as well as mimetite, duftite, cerussite, anglesite and wulfenite, and may be pseudomorphic after pyromorphite (common) or baryte.

At the Kintore Open Cut, New South Wales, Australia, plumbogummite occurs as a replacement of fluorapatite grains in a quartz-fluorapatite rock. It is also found at this locality as veins enclosing hinsdalite, in garnet sandstone.

At the New Cobar mine, New South Wales, Australia, plumbogummite occurs as small veinlets associated with malachite, azurite, cuprite and hematite.

At the type locality, Huelgoat, Brittany, France, plumbogummite occurs in a polymetallic lead vein with pyromorphite, cerussite, anglesite and wulfenite.

At Burdell Gill, Cumbria, UK, plumbogummite has been found encrusting goethite-coated quartz, associated with or replacing mimetite. It is also found as a coating on beudantite crystals at this locality.

At Roughton Gill, Cumbria, UK, plumbogummite occurs as encrustations on quartz or pyromorphite, occasionally overgrown by mottramite, and also associated with mimetite. It sometimes forms epimorphs after pyromorphite at this locality.

At the Mexico mine, Cumbria, UK, plumbogummite is associated with pyromorphite.

At the Canton mine, Cherokee county, Georgia, USA, plumbogummite is associated with marcasite.

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