Pyromorphite
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Pyromorphite is a mineral species composed of lead chlorophosphate: Pb 5 (PO 4 ) 3 Cl, sometimes occurring in sufficient abundance to be mined as an ore of lead. Crystals are common, and have the form of a hexagonal prism terminated by the basal planes, sometimes combined with narrow faces of a hexagonal pyramid. Crystals with a barrel-like curvature are not uncommon. Globular and reniform masses are also found. Pyromorphite is part of the apatite group of minerals and bears a close resemblance physically and chemically with two other minerals: mimetite (Pb 5 (AsO 4 ) 3 Cl) and vanadinite (Pb 5 (VO 4 ) 3 Cl). The resemblance in external characters is so close that, as a rule, it is only possible to distinguish between them by chemical tests. They were formerly confused under the names green lead ore and brown lead ore (German: Grünbleierz and Braunbleierz).
Pyromorphite is a mineral species composed of lead chlorophosphate: Pb 5 (PO 4 ) 3 Cl, sometimes occurring in sufficient abundance to be mined as an ore of lead. Crystals are common, and have the form of a hexagonal prism terminated by the basal planes, sometimes combined with narrow faces of a hexagonal pyramid. Crystals with a barrel-like curvature are not uncommon. Globular and reniform masses are also found. Pyromorphite is part of the apatite group of minerals and bears a close resemblance physically and chemically with two other minerals: mimetite (Pb 5 (AsO 4 ) 3 Cl) and vanadinite (Pb 5 (VO 4 ) 3 Cl). The resemblance in external characters is so close that, as a rule, it is only possible to distinguish between them by chemical tests. They were formerly confused under the names green lead ore and brown lead ore (German: Grünbleierz and Braunbleierz).
Properties
The color of the mineral is usually some bright shade of green, yellow or brown, and the luster is resinous. The hardness is 3.5 to 4, and the specific gravity between 6.5 and 7.1.
Gallery
File:Pyromorphite-137773.jpg|A pocket of crystals of pyromorphite from China File:Pyromorphite-157594.jpg|Miniature of sharp, lustrous, apple green color crystal "sprays" on matrix File:Pyromorphite-137954.jpg|Fine crystals of pyromorphite from Daoping Mine, Guangxi Zhuang Autonomous Region, China File:Pyromorphite-118273.jpg|Green pyromorphite crystals densely carpet the display side of the large matrix File:Pyromorphite-Cerussite-Caledonite-278353.jpg|Green pyromorphite microcrystals cover the vuggy, quartz-rich matrix. Seams of tiny cerussite crystals and crusts of contrasting, powder-blue caledonite round out this very rich lead ore specimen from an old Leadhills mine.
References
External links
Text derived from https://en.wikipedia.org/w/index.php?oldid=1325878027 under CC BY-SA 4.0; modifications have been made.