Pyromorphite

Pyromorphite
General
CategoryPhosphate mineral
Apatite group
Formula
(repeating unit)		Pb5(PO4)3Cl
IMA symbolPym[1]
Strunz classification8.BN.05
Crystal systemHexagonal
Crystal classDipyramidal (6/m)

(same H-M symbol)
Space groupP63/m
Identification
ColorDark green to grass-green or green, yellow, yellow-orange, reddish orange, yellow-brown, greenish-yellow or yellowish-green, shades of brown, tan, grayish, white and may be colorless; colourless or faintly tinted in transmitted light.
Crystal habitPrismatic to acicular crystals, globular to reniform
TwinningRarely on {1122}
CleavageImperfect- [1011]
FractureUneven to sub-conchoidal
TenacityBrittle
Mohs scale hardness3.5–4
LusterResinous to subadamantine
StreakWhite
DiaphaneityTransparent to translucent
Specific gravity7.04 measured, 7.14 calculated
Optical propertiesUniaxial (−) May be anomalously biaxial (−)
Refractive indexnω = 2.058 nε = 2.048
Birefringenceδ = 0.010
PleochroismWeak
Ultraviolet fluorescenceMay fluoresce yellow to orange under LW and SW UV
Other characteristicsPiezoelectric if biaxial
References[2][3][4]

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.[5] 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.[6] Crystals with a barrel-like curvature are not uncommon. Globular and reniform masses are also found.[7] Pyromorphite is part of the apatite group of minerals and bears a close resemblance physically and chemically with two other minerals: mimetite (Pb5(AsO4)3Cl) and vanadinite (Pb5(VO4)3Cl).[8] 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).[citation needed]

The phosphate was first distinguished chemically by M. H. Klaproth in 1784,[9][10][11][12] and it was named pyromorphite by J. F. L. Hausmann in 1813.[13][14] The name is derived from the Greek for pyr (fire) and morfe (form) due to its crystallization behavior after being melted.[3]

Paecilomyces javanicus is a mold collected from a lead-polluted soil that is able to form biominerals of pyromorphite.[15]

  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ Handbook of Mineralogy (PDF).
  3. ^ a b "Pyromorphite". Webmineral data.
  4. ^ "Pyromorphite". Mindat.org.
  5. ^ Cornelius S. Hurlbut; W. Edwin Sharp (1998). Dana's Minerals and How to Study Them (After Edward Salisbury Dana). John Wiley & Sons. p. 216. ISBN 978-0-471-15677-2.
  6. ^ Cornelis Klein; Barbara Dutrow (2007). Manual of Mineral Science. Wiley. p. 430. ISBN 978-0-471-72157-4.
  7. ^ A. Bishop; A. Woolley; W. Hamilton (1999). Cambridge Guide to Minerals, Rocks and Fossils. Cambridge University Press. p. 88. ISBN 978-0-521-77881-7.
  8. ^ Nicholas Eastaugh; Valentine Walsh; Tracey Chaplin; Ruth Siddall (2008). Pigment Compendium. Routledge. p. 320. ISBN 978-1-136-37392-3.
  9. ^ Klaproth (1784). Von dem Wassereisen, als einem mit Phosphorsäure verbundenen Eisenkalke (in German). On hydrosiderum [i.e., iron phosphide, Fe2P] as a calcined [i.e., roasted] iron [that is] bonded with phosphoric acid), Chemische Annalen für die Freunde der Naturlehre …, 1 (5) : 390–399. From p. 394: After remarking that lead ores that contain phosphorus can be treated with strong acids to produce phosphoric acid, Klaproth notes that: " … wie solches zuerst Hr. Gahn in Schweden entdeckt, ich selbst aber bey Unersuchung des krystallisirten grünen Bleyerzes von der heil. Dreyfaltigkeit zu Zschopau bestätigt gefunden habe." ( … as such Mr. Gahn in Sweden first discovered, I myself, however, have found [to be] confirmed by investigation of the crystallized green lead ore [i.e., pyromorphite] from the Holy Trinity at Zschopau in Germany]
  10. ^ Details of Klaproth's chemical analysis of pyromorphite appear in: Klaproth (1785) "Ueber die Phosphorsäure im Zschopauer grünen Bleyspathe" (On phosphoric acid in green lead spar from Zschopau), Beyträge zu den chemischen Annalen, 1 (1) : 13–21.
  11. ^ LXXXVII. Chemische Untersuchung der phosphorsauren Bleierze: I. Zeisiggrünes Bleierz von Zschopau. (87. Chemical investigation of the lead ores [containing] phosphoric acid: I. Siskin-green lead ore from Zschopau) in: Klaproth, Martin Heinrich, Beiträge zur chemischen Kenntnis der Mineralkörper [Contributions to our chemical knowledge of minerals]. Vol. 3. Posen, (Germany): Decker und Co.; Berlin, Germany: Heinrich August Rottmann. 1802. pp. 146–153.
  12. ^ Dr. Thomas Witzke. "Entdeckung von Pyromorphit (Discovery of pyromorphite)" (in German).
  13. ^ Hausmann, Johann Friedrich Ludwig (1813). Handbuch der Mineralogie. Göttingen, Germany: Vandenhoeck und Ruprecht. pp. 1090–1093.
  14. ^ Chester, Albert Huntington (1896). A Dictionary of the Names of Minerals Including Their History and Etymology. New York, New York: John Wiley & Sons. p. 224.
  15. ^ Rhee, Young Joon; Hillier, Stephen; Pendlowskic, Helen; Gadd, Geoffrey Michael (October 2014). "Fungal transformation of metallic lead to pyromorphite in liquid medium". Chemosphere. 113: 17–21. Bibcode:2014Chmsp.113...17R. doi:10.1016/j.chemosphere.2014.03.085. PMID 25065784. Retrieved 2024-11-12.