| Eosphorite | |
|---|---|
Rose Quartz with Eosphorite |
|
| General | |
| Category | Phosphate mineral |
| Chemical formula | 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]
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