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Hureaulite

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(Redirected from Huréaulite) Manganese phosphate mineral
Hureaulite
Hureaulite from the Cigana Claim, Conselheiro Pena, Minas Gerais, Brazil. Specimen size 2.8 cm.
General
CategoryPhosphate minerals
Formula
(repeating unit)		Mn5(PO3OH)2(PO4)2·4H2O
IMA symbolHur
Strunz classification8.CB.10 (10 ed)
7/C.04-10 (8 ed)
Dana classification39.2.1.1
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupC2/c
Unit cella = 17.594(10) Å
b = 9.086(5) Å
c = 9.404(5) Å
β = 96.67(8)°; Z = 4
Identification
Formula mass728.65 g/mol
ColourOrange, red, yellow, brown, grey or nearly colourless
Crystal habitCrystals are short prismatic parallel to (100) or equant, sometimes thick tabular, also massive or imperfectly fibrous
Cleavage{100} good
FractureUneven
TenacityBrittle
Mohs scale hardness3.5
LustreVitreous to greasy
StreakNearly white
DiaphaneityTransparent to translucent
Specific gravity3.18–3.2 (measured), 3.23 (calculated)
Optical propertiesBiaxial (−)
Refractive indexnα = 1.640 – 1.654 nβ = 1.649 – 1.659 nγ = 1.655 – 1.662
Birefringenceδ = 0.012
PleochroismX colourless, Y yellow to pale rose, Z reddish yellow to reddish brown
2V anglegreater than 60°
Dispersionr<v, very strong
SolubilityEasily soluble in acids.
References

Hureaulite is a manganese phosphate with the formula Mn5(PO3OH)2(PO4)2·4H2O. It was discovered in 1825 and named in 1826 for the type locality, Les Hureaux, Saint-Sylvestre, Haute-Vienne, Limousin, France. It is sometimes written as huréaulite, but the IMA does not recommend this for English language text.

A complete series exists from lithiophilite, LiMnPO4 to triphylite, LiFePO4, including hureaulite, strengite, FePO4·2H2O, stewartite, MnFe2(OH,PO4)2·8H2O, and sicklerite, (LiMn,Fe)PO4.

Environment

Hureaulite is a secondary mineral occurring in granite pegmatites. At the type locality it occurs in a zone of altered triphylite, LiMnPO4, in pegmatite. Typically occurs very late in the sequence of formation of secondary phosphate minerals. Associated at the type locality with vivianite, Fe3(PO4)2·8H2O; rockbridgeite, FeFe4(PO4)3(OH)5; heterosite, (Fe,Mn)PO4 and cacoxenite, Fe24AlO6(PO4)17(OH)12·17H2O. It can be synthesised; most natural hureaulites are Mn-rich compounds but extensive (Mn,Fe) solution is known for synthetic material.

Localities

The type locality is Les Hureaux, Saint-Sylvestre, Haute-Vienne, Limousin, France. Hureaulite is also found in a granite pegmatite known for its phosphates in the Aimorés pegmatite district, at the Cigana claim in Galiléia, Doce valley, Minas Gerais, Brazil, formerly known as the Jocão Mine.

References

  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. Murdoch, Joseph (1942) Contributions to the Crystallography of Hureaulite. American Mineralogist 27: 228
  3. ^ Gaines et al (1997) Dana's New Mineralogy Eighth Edition
  4. ^ http://www.mindat.org/min-1952.html Mindat.org
  5. Shigley and Brown (1985) American Mineralogist 70:395
  6. ^ Roberts, Campbell and Rapp (1990) Encyclopedia of Minerals, 2nd edition
  7. Burke, E. A. J. (2008): Tidying up Mineral Names: An IMA scheme for Suffixes, Hyphens and Diacritical Marks. Mineralogical Record, 39, 134
  8. Murdoch, Joseph (1943) Crystallography of Hureaulite. American Mineralogist 28: 19-24
  9. ^ Moore, P B, and Araki, T (1973) Hureaulite: its atomic arrangement. American Mineralogist 58: 302-307.
  10. Gerault, Y, Riou, A, and Cudennec, Y (1987) Acta Crystallographica (C) 43:1829
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