Pyromorphite

Pyromorphite

Infobox mineral
name = Pyromorphite
category = Mineral
boxwidth =
boxbgcolor =


imagesize = 250px
caption = Yellow pyromorphite from Australia
formula = Pb5(PO4)3Cl
molweight = 1,356.37 gm
color = Colorless, Green, Yellow, etc...
habit = massive to crystaline
system = Hexagonal
twinning =
cleavage = Imperfect- [1011]
fracture = Brittle
tenacity = Brittle
mohs = 3.5-4
luster = vitreous
polish =
refractive =
opticalprop =
birefringence =
dispersion =
pleochroism =
fluorescence= None
absorption =
streak = White
gravity =
density = 7.109 g/cm3
melt =
fusibility =
diagnostic =
solubility =
diaphaneity = Transparent to opaque
other =
references =

Pyromorphite is a mineral species composed of lead chlorophosphate: Pb5(PO4)3Cl, 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. It is part of a series with two other minerals: mimetite (Pb5(AsO4)3Cl) and vanadinite (Pb5(VO4)3Cl), 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). The phosphate was first distinguished chemically by M. H. Kiaproth in 1784, and it was named pyromorphite by J. F. L. Hausmann in 1813.

The color of the mineral is usually some bright shade of green, yellow or brown, and the luster is resinous. The hardness is 3, and the specific gravity 6.5 - 7.1. Owing to isomorphous replacement of the phosphorus by arsenic there may be a gradual passage from pyromorphite to mimetite. Varieties containing calcium isomorphously replacing lead are lower in density (specific gravity 5.9 - 6.5) and usually lighter in color; they bear the names polysphaerite (because of the globular form), miesite from Mies in Bohemia, nussierite from Nuizière, Chénelette, near Beaujeu, Rhône, France, and cherokine from Cherokee County in Georgia.

See also

* List of minerals

References

*1911


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Look at other dictionaries:

  • Pyromorphite — Catégorie VIII : phosphates, arséniates, vanadates[1] Pyromorphite Ussel, Correze France (4x4cm) …   Wikipédia en Français

  • Pyromorphite — Pyr o*mor phite, n. [G. pyromorphit, from Gr. ? fire + morfh form.] (Min.) Native lead phosphate with lead chloride, occurring in bright green and brown hexagonal crystals and also massive; so called because a fused globule crystallizes in… …   The Collaborative International Dictionary of English

  • pyromorphite — ● pyromorphite nom féminin Chlorophosphate naturel de plomb, hexagonal, que l on trouve à la partie supérieure des gisements de galène …   Encyclopédie Universelle

  • pyromorphite — [pī΄rə môr′fīt΄] n. [Ger pyromorphit: see PYRO & MORPH & ITE1] a semihard, greenish, hexagonal mineral, Pb5 (PO4) 3Cl, an ore of lead; lead phosphate chloride …   English World dictionary

  • pyromorphite — /puy reuh mawr fuyt/, n. a mineral, lead chlorophosphate, Pb5P3O12Cl, occurring in crystalline and massive forms, and of a green, yellow, or brown color; green lead ore: a minor ore of lead. [1805 15; < G Pyromorphit. See PYRO , MORPH , ITE1] * * …   Universalium

  • pyromorphite — piromorfitas statusas T sritis chemija apibrėžtis Mineralas. formulė Pb₅[Cl|(PO₄)]₃ atitikmenys: angl. pyromorphite rus. пироморфит …   Chemijos terminų aiškinamasis žodynas

  • pyromorphite — noun a mineral consisting of lead chloride and phosphate; a minor source of lead • Syn: ↑green lead ore • Hypernyms: ↑mineral * * * pyromorphite, morphous see pyro 2, 1 …   Useful english dictionary

  • pyromorphite — noun Etymology: German Pyromorphit, from Greek pyr + morphē form Date: circa 1814 a mineral consisting essentially of a chloride and phosphate of lead …   New Collegiate Dictionary

  • pyromorphite — noun A yellowish green mineral, a mixed phosphate and chloride of lead with the chemical formula Pb(PO)Cl, that is sometimes mined as an ore …   Wiktionary

  • pyromorphite — (pi ro mor fi t ) s. f. Phosphate de plomb naturel …   Dictionnaire de la Langue Française d'Émile Littré

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