Triplite Explained

Triplite
Category:Phosphate minerals
Formula:(Mn,Fe)2(PO4)(F,OH)
Imasymbol:Trl[1]
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
Cleavage:Good on, fair on, poor on
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
Pleochroism:Distinct; yellow-brown to reddish brown
Streak:White to brown
Gravity:3.5 – 3.9
Diaphaneity:Translucent to opaque
Alteration:Alters to brownish black
References:[2] [3] [4] [5]

Triplite is a rare phosphate mineral with formula: . 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 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]

Notes and References

  1. Warr. L.N.. 2021. IMA–CNMNC approved mineral symbols. Mineralogical Magazine. 85. 3. 291–320. 10.1180/mgm.2021.43. 2021MinM...85..291W. 235729616. free.
  2. http://rruff.geo.arizona.edu/doclib/hom/triplite.pdf Handbook of Mineralogy
  3. http://www.mindat.org/min-4021.html Mindat.org
  4. http://webmineral.com/data/Triplite.shtml Webmineral data
  5. Vignola . Pietro . Gatta . G. Diego . Hatert . Frédéric . Guastoni . Alessandro . Bersani . Danilo . 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 . April 2014 . 52 . 2 . 235–245 . 10.3749/canmin.52.2.235.
  6. http://www.minsocam.org/msa/collectors_corner/arc/tripliteco.htm Triplite Crystals from Colorado