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The Mineral pyromorphite

Bright Green Pyromorphite Hexagons

Pyromorphite is a member of the Apatite group, a group of isomorphous hexagonal minerals. It is very similar in structure and appearance to Mimetite, and may be partially replaced by it. In fact, sometimes Pyromorphite and Mimetite are virtually indistinguishable from each other and may be wrongly labeled as the other.

Chemical Formula

Pb5(PO4)3Cl

Color

Light to dark green, yellow-green, greenish-white, brownish-green, brown, orange, gray, and white. May also be multicolored green and orange.

Crystal System

Hexagonal

Properties

Streak
White
Hardness
3.5 - 4
Transparency
Translucent
Specific Gravity
6.9 - 7.1
Luster
Resinous to greasy
Cleavage
None
Fracture
Subconchoidal to uneven
Tenacity
Brittle

Crystal Habits

Occurs as barrel-like hexagonal crystals, which are usually grouped together in interesting aggregates, and may be bipyramidal. Also acicular, crusty, grainy, radiating, reniform, botryoidal and in curvy aggregates. Some larger crystals may be hollowed out on the ends or have a hopper growth pattern.

3D Crystal Atlas

Additional Information

Composition
Lead chloro-phosphate. The phosphate radical (PO4) may be partially replaced by an arsenate radical (AsO4), thus forming a series with Mimetite.
In Group
Phosphates; True Phosphates; Apatite Group
Striking Features
Color, hollow crystals, crystal habits, and localities
Environment
As a secondary mineral in the oxidation zone of lead ore deposits.
Rock Type
Sedimentary, Metamorphic

Other Names

Green Lead Ore

Uses

Pyromorphite is a minor ore of lead where it occurs with more abundant lead minerals. It is also a popular mineral among collectors, especially specimens from classic occurrences, as well as newer finds of bright neon green Pyromorphite which command very high prices.

Noteworthy Localities

This mineral contains many classic and exceptional localities. High up on the list is the Bad Ems District, Rhineland, Germany, where large stubby, and often brownish crystals are affectionately called "Emser Barrels". Other very famous and classic European localities are the Les Farges Mine, Correze, France; Cordoba, Andalusia, Spain; El Horcajo, Ciudad Real, Spain; and Caldbeck Fells, Cumbria, England. Fine globular and mammilary Pyromporphite comes from the S'Ortu Becciu Mine in Cagliari Province, Sardinia, Italy.

Many outstanding specimens have recently been coming out of China, with an exceptional brilliant apple-green color that almost looks too artificial to be real. These specimens come from the Daoping and adjacent Yangshuo Mine in Gongcheng, Guangxi, China.

Australia also contains many fabulous occurrences, specifically Broken Hill, New South Wales; the Rum Jungle, Batchelor, Northern Territory; the Black Star Mine, Mount Isa, Queensland; and Zeehan, on the island of Tasmania. Large plates have come from the Broken Hill Mine, Kabwe, in the African country of Zambia.

In Mexico, light green crystals associated with Wulfenite come from Mapimi, Durango; and nice crystal clusters from the
San Luis Mine, San Jose, Chihuahua. In Canada, specimens were found in the Society Girl Mine in Moyie, British Columbia.

In the U.S., the finest specimens are from the Coeur d'Alene District in Shoshone Co., Idaho. This area has several prolific mines, with the most notable being the Bunker Hill Mine in Kellogg, where outstanding green and orange crystals and sparkling globular masses were found. The most classic U.S. locality is Phoenixville, Chester Co., Pennsylvania, which has produced some famous old-time examples, especially from the famed Wheatley Mines. Another old locality, which contains mostly microcrystals, is the Loudville Lead Mine, in Easthampton, Hampshire Co., Massachusetts.

Common Mineral Associations

Limonite, Galena, Barite, Vanadinite, Cerussite, Wulfenite, Hemimorphite, Quartz

Distingushing Similar Minerals

Mimetite - Usually yellower in color, and less commonly in hollow crystals. Otherwise cannot be distinguished with simple methods.
Vanadinite - Usually more red in color, has a slightly yellow streak, and is slightly softer. Otherwise cannot be distinguished with simple methods.
Apatite - Harder (5).


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