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THE MINERAL PYROMORPHITE

  • Chemistry: Pb5(PO4)3Cl , Lead Chlorophosphate
  • Class: Phosphates
  • Group: Apatite
  • Uses: as a minor ore of lead and mineral specimens
  • Specimens

[/_inline.htm]Pyromorphite shares the same structure with apatite and therefore crystals of the two will have similar shapes. Pyromorphite also forms a chemical series with two other minerals; Mimetite (Pb5(AsO4)3Cl) and Vanadinite (Pb5(VO4)3Cl). This series is a little different than most chemical series which involve substitution of cations such as calcium for magnesium. Instead, this series substitutes its basic chemical units the anion groups; phosphate (PO4), arsenate (AsO4) and vanadate (VO4). Green Mimetite or yellow Pyromorphite can make identification between the two difficult, but usually pyromorphite is green and mimetite is yellow. Vanadinite is usually red. Pyromorphite's main characteristic is its unique crystal habit of stacked barrel shaped crystals that branch out in a way that is reminescent of some branching cactus varieties.

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PHYSICAL CHARACTERISTICS:

  • Color is typically green, but can also be yellow, orange and brown.
  • Luster is resinous to adamantine.
  • Transparency: Crystals are rarely transparent, but usually translucent.
  • Crystal System is hexagonal; 6/m
  • Crystal Habits include the typical barrel shaped hexagonal prism with the hexagonal pyramid and/or a pinacoid as a termination. A classic specimen of Pyromorphite shows its arborescent habit as described above. Also granular, reniform, encrusting and massive.
  • Cleavage is absent.
  • Fracture is uneven.
  • Hardness is 3.5 - 4.
  • Specific Gravity is approximately 7.0+ (very heavy for translucent minerals)
  • Streak is off white.
  • Associated Minerals are cerussite, limonite, galena and secondary lead deposit minerals.
  • Other Characteristics: Index of refraction is 2.05 (typically high for lead minerals) and crystal terminations can be hollowed out or pitted.
  • Notable Occurrences include Idaho and Pennsylvania, USA; Mapimi, Mexico; Germany; England and Australia.
  • Best Field Indicators are crystal habit, color, lack of transparency and density.
This Site Awarded
Available PYROMORPHITE specimens:
PYROMORPHITE specimen PYM-14
$ 600.00 -55% = $ 270.00
Dims: 2.6x3.2x2.2" (6.6x8.1x5.5cm) .... Wt: 14.66 oz. (414.9g) .... Loc: Dao Ping Mine, Yang Suo Guang Xi Province, China
This is a wonderful and large pyromorphite specimen. The crystals are translucent, and most of them are the preferred pale-olive-green, although there is a smooth shading to a pale gray-green towards one side of the base of the specimen. The crystals individually have the classic pyromorphite shape (sometimes described as tapered pseudo-hexagonal barrel shaped), although the arborescent branching is not here. Rather, many crystals simply rise from the matrix, and others are in somewhat radial clusters. Some of the crystals are curved and approach 2cm in length. At one end (or the top, depending upon your viewpoint) there is a relatively large cluster creating a "C" shaped specimen. There is a large amount of pyromorphite here, and the crystals are relatively large. They are undamaged, except at the edges, although there is an odd pattern in the center of the largest cluster making it look like some central crystals are missing, and some bent. My examination suggests that if this happened, it was during the formation of the specimen, as the crystals are all firmly attached and there is no sign of cleavage or parting. It is possible that some other mineral interferred with crystal growth, and since disolved away. In any case, this is a great cabinet specimen of pyromorphite.
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PYM-14
$ 270.00
no photo
PYROMORPHITE specimen PYM-22
$ 30.00 -20% = $ 24.00
Dims: 2.27x1.44x1.15in (5.76x3.66x2.93cm) .... Wt: 2.83oz (80.0g) .... Loc: Brookdale Shaft, Wheatley Mine, Phoenixville, Pennsylvania, USA
The color of these photos is only correct for bright light such as quartz halogen; under normal incandescent lighting, the green is much more muted. This is an example of a pyromorphyte druze; the individual crystals are barely large enough to show crystal form and a waxy luster with the aid of a 10 power loupe.
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PYM-22
$ 24.00
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see this List of ALL specimens including SOLD ones

 

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