Eosphorite

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Eosphorite

Rose Quartz with Eosphorite
General
Category Phosphate mineral
Formula
(repeating unit)
MnAl(PO4)(OH)2·H2O
Strunz classification 08.DD.20
Crystal symmetry Monoclinic 2/m prismatic
Unit cell a = 10.455(1) Å, b = 13.501(2) Å, c = 6.928(1) Å; β = 90°; Z = 8
Identification
Color Pink, rose red
Crystal habit Prismatic in radiating sprays or spheres, massive
Crystal system Monoclinic
Twinning May be observed on {100} and {001}
Cleavage Poor on {100}
Fracture Subconchoidal to uneven
Mohs scale hardness 5
Luster Vitreous, resinous
Streak White
Diaphaneity Transparent to translucent
Specific gravity 3.06 – 3.08
Optical properties Biaxial (-)
Refractive index nα = 1.628 - 1.639 nβ = 1.648 - 1.664 nγ = 1.657 - 1.671
Birefringence δ = 0.029 - 0.032
Pleochroism Visible: X = yellow; Y = pink; Z = pale pink to colorless
2V angle Measured: 50°
Alters to Oxidizes to brown or black
References [1][2][3]

Eosphorite is a pink manganese phosphate mineral with chemical formula: MnAl(PO4)(OH)2·H2O.[4]

Eosphorite crystallizes in the monoclinic crystal system. It forms prismatic crystals which often form radiating or spherical clusters. The crystals often show pseudo–orthorhombic forms due to twinning.[3]

It was first described in 1878 for an occurrence in the Branchville Mica Mine in Branchville, Fairfield County, Connecticut, USA. Its name is derived from the Greek έωσφορος for "dawn-bearing," because of its pink color.[2] It occurs worldwide typically as a secondary mineral in pegmatites in association with rhodochrosite, lithiophilite, triploidite, dickinsonite, albite, cookeite, apatite, beryllonite, hydroxyl-herderite and tourmaline.[3]

References

  1. Eosphorite, WebMineral.com, retrieved 2011-01-30 
  2. 2.0 2.1 Eosphorite, MinDat.org, retrieved 2011-01-30 
  3. 3.0 3.1 3.2 Handbook of Mineralogy
  4. Fleischer, Michael & Mandarino, Joseph, "Glossary of Mineral Species", The Mineralogical Record, 1991
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