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| Chemistry:
Pb5(PO4)3Cl
[Lead Chlorophosphate] | Discovered
in 1813;
IMA
status: Valid (pre-IMA; Grandfathered). Named in 1813 from the Greek pyr
for "fire" and morfe for "form" because after being melted
into a globule a sample will begin to take on a crystalline shape during
cooling. |
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Classification
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Mineral
Classification: |
Phosphates |
Strunz 8th
Ed. ID:
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7/B.39-150
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Nickel-Strunz 10th
Ed. ID:
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8.BN.05 |
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8 : PHOSPHATES, ARSENATES, VANADATES B : Phosphates, etc.,
with additional anions, without H2O N : With only large cations,
(OH, etc.):RO4 = 0.33:1
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Related
to: |
A
member of the Apatite Group, Pyromorphite Subgroup,
Mimetite-Pyromorphite Series. It is the phosphate analogue
of and is isostructural with Mimetite and Vanadinite.
It also forms a series with an unnamed OH-analogue of
Pyromorphite.
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Crystal
Data
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Crystallography:
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Hexagonal - Dipyramidal
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Crystal
Habit:
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Crystals
short to long prismatic, may be acicular [0001], with
prominent [1010], [0001], [1011], [2021], hoppered terminations
typical, to 8 cm, rarely tabular to equant; radiating
to branching groups, tapering to a point. Commonly rounded,
globular, reniform, botryoidal.
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Twinning:
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On
[1122], very rare
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Physical
Properties
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Cleavage: |
[1011]
Imperfect
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Fracture: |
Irregular,
Uneven, Subconchoidal
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Tenacity:
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Brittle
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Hardness
(Mohs): |
3.5 - 4.0
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Density:
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7.04 (g/cm3)
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Luminescence:
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None
or may fluoresce yellow to orange under LW and SW UV. |
Radioactivity:
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Not
Radioacitve |
Other: |
Piezoelectric
if Biaxial (may
be anomalously Biaxial) |
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Optical
Properties
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Color: |
Green, Yellow, Brown, Grayish White, Yellowish Red
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Transparency: |
Transparent
to Translucent |
Luster: |
Adamantine,
Resinous |
Refractive
Index: |
2.049
- 2.059 Uniaxial ( - ); may be anomalously
Biaxial ( - ), sectored
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Birefringence: |
0.0100
(very high)
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Dispersion: |
Very
Strong; r > v |
Pleochroism: |
Weak |
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Occurances
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Geological
Setting: |
A
secondary mineral in the oxidized zone of lead deposits;
rarely a volcanic sublimate. |
Common
Associations: |
Anglesite,
Cerussite, Galena, Plumbogummite, Smithsonite, Silver,
Willemite |
Type
Locality: |
n/a |
Year
Discovered: |
1813
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View
mineral photos: |
Pyromorphite
Mineral Photos and Locations |
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More
Information
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Mindat.org Webmineral.com
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Pyromorphite
is a fairly common mineral but very rarely faceted.
It is a secondary lead mineral found in the oxidized zones of lead deposits. Typically
found as green to yellow barrel-shaped hexagonal prisms, in clusters or as
druses on matrix. Pyromorphite has the same structure as Apatite so
crystals of the two will have similar shapes. Pyromorphite also forms a chemical
series with Mimetite (Pb5(AsO4)3Cl) and Vanadinite (Pb5(VO4)3Cl). It
can be very difficult to tell the difference between
green Mimetite or yellow Pyromorphite, but usually Pyromorphite is green and Mimetite is yellow. Vanadinite
is usually red.
The
main sources of large, bright green, gemmy crystals
are Guilin Prefecture, Guangxi Zhuang Autonomous Region,
China; Ussel, Corrčze, Limousin, France, Villaviciosa de Córdoba, Sierra
Morena, Córdoba, Andalusia, Spain; and Coeur d'Alene District, Shoshone County, Idaho, USA.
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Pyromorphite
gems for sale:
We
have not photographed the Pyromorphite gems. Please
check back soon.
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