Pyrobelonite



Pyrobelonite is a lead manganese vanadate hydroxide mineral related to descloizite (perhaps explaining Palache's incorrect assignment of species). A microprobe analysis yielded CaO 0.3, FeO 0.3, ZnO 0.4, MnO 18.7, PbO 54.3, SiO2 2.2, V2O5 20.3, with H2O from the theoretical composition at 2.3, total = 98.8 wt. %.
Pyrobelonite was first noted by Palache (1935) who described it as descloizite from Franklin; it was subsequently found to be pyrobelonite (Dunn, 1983a), which is unknown from Sterling Hill.
Pyrobelonite occurs as bright red, prismatic, tapering, 0.3 mm crystals. The color is similar to that of proustite, but pyrobelonite lacks the submetallic luster of that species. The crystals taper gradually to a point and on casual examination appear to be tiny zincite crystals. No physical or optical data have been obtained; the mineral was verified by X-ray methods and chemical analysis, which are suggested for verification.
Pyrobelonite occurs on willemite/franklinite ore which is encrusted with a druse of andradite and isolated crystals of tephroite, clinochlore, and willemite. Pyrobelonite occurs as a sprinkling of tiny red crystals on all these minerals and is in turn coated with hodgkinsonite of unusual habit and barite. Few specimens of this superb assemblage are known; the richest specimen is at Harvard University. (Dunn, 1995)


 Location Found: Franklin
     
 
 Year Discovered: 1919
     
 Formula: PbMn2+(VO4)(OH)
 Essential Elements: Hydrogen, Lead, Manganese, Oxygen, Vanadium
 All Elements in Formula: Hydrogen, Lead, Manganese, Oxygen, Vanadium
     
 IMA Status: Valid - first described prior to 1959 (pre-IMA) - "Grandfathered"
     
     
 To find out more about this mineral at minDat's website, follow this link   Pyrobelonite

     
 References:
Dunn, Pete J. (1995). Franklin and Sterling Hill New Jersey: the world's most magnificent mineral deposits. Franklin, NJ.: The Franklin-Ogdensburg Mineralogical Society. p.677


The Picking Table References
 PT Issue and PageDescription / Comment
View IssueV. 25 No. 1 - Spring 1984, pg. 10Mineral Notes Research Reports, Pyrobelonite
     
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