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Pyromorphite Mineral Facts:

Chemical Formula: Pb₄(PbCl)(PO₄)₃ 

Colors: Mineral is green, yellow, brown or orange. Streak is white.

Hardness: 3.5 to 4.0

Density: 6.5 to 7.1
The density is high because of the large lead content. 

Cleavage: Perfect parallel to the faces

Crystallography: Hexagonal

Luster:. Resinous luster.

Optics: (Refractive Index): w = 2.061; e = 2.049

Composition, Structure and Associated Minerals:
Crystals are often rounded into barrel-shaped forms, and frequently are mere skeletons. Tapering groups of slender crystals in parallel growths are also common.  Often in rounded barrel-shaped forms. Sometimes cavernous, the crystals being hollow prisms.  The mineral also occurs in globular, granular and fibrous masses.

Identification and Diagnostics
It fuses easily, coloring the flame bluish green. When heated on charcoal it melts to a globule of lead, which  crystallizes on cooling and yields a coating which is yellow near the assay and white, at a greater distance from it. The mineral also gives positive reactions for Cl and P reactions. The mineral is soluble in nitric acid. Pyromorphite is recognized by its form, high specific gravity and its action when heated on charcoal.

Occurrence, Localities and Origins:
Pyromorphite is found in company with other secondary ores of lead, such as cerussite, angelesite. When plentiful, is smelted with the other lead ores. It is found in all lead-producing regions, especially in the upper, oxidized portions of veins. It occurs in particularly good specimens at Pribram, Bohemia; at Ems, in Nassau; in Cornwall, Devon, Derbyshire and Cumberland, England; at Phoenixville, Pennsylvania, and at various other points in the Appalachian region.

Uses. Pyromorphite alone is of significant value only if the mineral specimens are well-crystallized, colorful and showy. In other forms it is mined with other compounds of lead as an ore of this metal.

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Pyromorphite, Arsenic Bearing Form

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