Pyromorphite


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Related to Pyromorphite: Mimetite

pyromorphite

[¦pī·rō′mȯr‚fīt]
(mineralogy)
Pb5(PO4)3Cl A green, yellow, brown, gray, or white mineral of the apatite group, crystallizing in the hexagonal system; a minor ore of lead. Also known as green lead ore.

Pyromorphite

 

a mineral with the formula Pb5[PO4]3Cl. Pyromorphite contains 82.0 percent PbO, 15.4 percent P2O5, and 2.6 percent Cl. Sometimes it has admixtures of As, which substitutes for phosphorus. Pyromorphite crystallizes in the hexagonal system, forming prismatic or barrel-shaped crystals and, more rarely, granular, fibrous, and sintered aggregates. It has a hardness of 3.5–4 on Mohs’ scale and a density of 6,700–7,100 kg/m3. Pyromorphite is a brittle mineral. Its color is usually various shades of green, occasionally yellow, orange, or some other color.

Pyromorphite occurs in oxidation zones of lead and lead-zinc deposits. It is also associated with other lead minerals, such as cerussite, anglesite, mimetite, vanadinite, and wulfenite. Pyromorphite does not form large aggregates. It is used, along with other lead minerals, in the extraction of metallic lead.

References in periodicals archive ?
It has also been found in float with minute white sprays of pyromorphite, hemimorphite and chrysocolla after malachite.
The exceptional pyromorphite from Roughton Gill, LG-30, is one of the finest Greenbank pieces from the Lanfine collection.
Members of the pyromorphite group that occur there include matt-heddleite, mimetite.
He is particularly associated with the world-renowned pyromorphite, mimetite, hemimorphite, and linarite from Caldbeck, and also did a good trade in rare lead minerals from Leadhills and Wanlockhead in Scotland.
Pyromorphite Friedrichssegen Mine Ems, Nassau, Germany 5" tall ex-collection British Museum (Natural History)
And micromounters take note: hiding in the copper, in some cases, are sharp, tiny crystals of cerussite, silver, pyromorphite, iodargyrite, and probably an unknown or two.
In 1967 he moved back to Massachusetts where he settled in Millis, and began exploring New England mines, collecting fluorite in Westmoreland, New Hampshire, amethyst in Bellingham, and pyromorphite in Loudville, Massachusetts.
There were very extensive representations from the Broken Hill collections of Milton Lavers and Rod Sielecki, and I still cherish images of certain specimens of copper, rhodonite, pyromorphite,anglesite, smithsonite, cerussite ...
Maybe pyromorphite? But is the chemistry right for this paragenesis?
The use of phosphates has been shown to be effective in reducing toxicity and mobility of lead through the formation of insoluble and geochemically stable lead pyromorphites (Chen et al., 1997).
He is perhaps most remembered for introducing world-class Bunker Hill pyromorphites to the collecting world at the 1982 Tucson Gem and Mineral Show.
Although these photographs, and the specimens which are their subjects, vary considerably in quality, some of the best of the latter are truly superb--the pyromorphites. anglesites, cerussites and wulfenites from Phoenixville, the pyrites and chalcopyrites from French Creek, the rutile from Parkesburg, such as the apatite-(CaF) from Cornog--while others are quite surprising, even to this Pennsylvania native, e.g.