Triplite
{{Short description|Phosphate mineral}}
{{Infobox mineral
| name = Triplite
| category = Phosphate minerals
| image = Triplite-t5105a.jpg
| imagesize =
| caption = Triplite from Alchuri, Shigar Valley, Baltistan, Pakistan (1.2 × 1 × 0.9 cm)
| formula = (Mn,Fe)2(PO4)(F,OH)
| molweight =
| strunz = 8.BB.10
| system = Monoclinic
| class = Prismatic (2/m)
(same H-M symbol)
| symmetry = I2/a (no. 15)
| unit cell = a = 11.97 Å, b = 6.52 Å
c = 10.09 Å; β = 105.62°; Z = 8
| color = Chestnut to reddish brown, flesh-red, salmon-pink
| habit = Prismatic, massive to nodular
| twinning =
| cleavage = Good on {001}, fair on {010}, poor on {100}
| fracture = Uneven to subconchoidal
| mohs = 5 to 5.5
| luster = Vitreous to resinous
| refractive = nα=1.643–1.684, nβ=1.647–1.693, nγ=1.668–1.703
| opticalprop = Biaxial (+)
| 2V = 25 – 76°
| dispersion = r > v, moderate to strong
| birefringence =
| pleochroism = Distinct; yellow-brown to reddish brown
| streak = White to brown
| gravity = 3.5 – 3.9
| density =
| melt =
| fusibility =
| diagnostic =
| solubility =
| diaphaneity = Translucent to opaque
| alteration = Alters to brownish black
| other =
| references = [http://rruff.geo.arizona.edu/doclib/hom/triplite.pdf Handbook of Mineralogy][http://www.mindat.org/min-4021.html Mindat.org][http://webmineral.com/data/Triplite.shtml Webmineral data]{{cite journal |last1=Vignola |first1=Pietro |last2=Gatta |first2=G. Diego |last3=Hatert |first3=Frédéric |last4=Guastoni |first4=Alessandro |last5=Bersani |first5=Danilo |title=ON THE CRYSTAL-CHEMISTRY OF A NEAR-ENDMEMBER TRIPLITE, Mn 2+ 2 (PO 4 )F, FROM THE CODERA VALLEY (SONDRIO PROVINCE, CENTRAL ALPS, ITALY) |journal=The Canadian Mineralogist |date=April 2014 |volume=52 |issue=2 |pages=235–245 |doi=10.3749/canmin.52.2.235|bibcode=2014CaMin..52..235V |url=https://orbi.uliege.be/bitstream/2268/188054/1/Triplite-Pietro.pdf }}
}}
Triplite is a rare phosphate mineral with formula: {{chem2|(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.[http://www.minsocam.org/msa/collectors_corner/arc/tripliteco.htm Triplite Crystals from Colorado], C. W. Wolf and E. Wm. Heinrich, American Mineralogist, Volume 32, pages 518–526, 1947 The name is from the Greek triplos for triple, in reference to the three cleavage directions. 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
Image:Triplite Manganese iron fluophosphate Jefferson County Colorado 1824.jpg]]
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.
References
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