Triplite

(repeating unit)(Mn,Fe)2(PO4)(F,OH)IMA symbolTrl[1]Strunz classification8.BB.10Crystal systemMonoclinicCrystal classPrismatic (2/m)
(same H-M symbol)Space groupI2/a (no. 15)Unit cella = 11.97 Å, b = 6.52 Å
c = 10.09 Å; β = 105.62°; Z = 8IdentificationColorChestnut to reddish brown, flesh-red, salmon-pinkCrystal habitPrismatic, massive to nodularCleavageGood on {001}, fair on {010}, poor on {100}FractureUneven to subconchoidalMohs scale hardness5 to 5.5LusterVitreous to resinousStreakWhite to brownDiaphaneityTranslucent to opaqueSpecific gravity3.5 – 3.9Optical propertiesBiaxial (+)Refractive indexnα=1.643–1.684, nβ=1.647–1.693, nγ=1.668–1.703PleochroismDistinct; yellow-brown to reddish brown2V angle25 – 76°Dispersionr > v, moderate to strongAlters toAlters to brownish blackReferences[2][3][4][5]

Triplite is a rare phosphate mineral with formula: (Mn, Fe)2PO4(F, OH). It occurs in phosphate-rich granitic pegmatites typically as irregular brown opaque masses. Triplite was first described in 1813 for an occurrence in Chanteloube, Limousin, France.[6] The name is from the Greek triplos for triple, in reference to the three cleavage directions.[3] In color and appearance, it is very similar to rhodocrosite, another manganese bearing mineral. Chemically, it is also quite similar to triploidite the difference being that triplite is fluorine dominant while triploidite is hydroxide dominant.

Occurrence

Triplite from Colorado

Triplite is a rare fluoro-hydroxide phosphate mineral that forms in phosphate rich granite pegmatites and high temperature hydrothermal veins. It has been found in the United States in California, Nevada, Arizona, Colorado, South Dakota, Virginia, Connecticut, and Maine. Other occurrences include the Shigar Valley, Pakistan; China; Bavaria, Germany; Kimito, Finland and Karibib, Namibia.[3]

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. ^ Handbook of Mineralogy
  3. ^ a b c Mindat.org
  4. ^ Webmineral data
  5. ^ Vignola, Pietro; Gatta, G. Diego; Hatert, Frédéric; Guastoni, Alessandro; Bersani, Danilo (April 2014). "ON THE CRYSTAL-CHEMISTRY OF A NEAR-ENDMEMBER TRIPLITE, Mn 2+ 2 (PO 4 )F, FROM THE CODERA VALLEY (SONDRIO PROVINCE, CENTRAL ALPS, ITALY)". The Canadian Mineralogist. 52 (2): 235–245. doi:10.3749/canmin.52.2.235.
  6. ^ Triplite Crystals from Colorado, C. W. Wolf and E. Wm. Heinrich, American Mineralogist, Volume 32, pages 518–526, 1947

External links

Media related to Triplite at Wikimedia Commons

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