perhamite
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Perhamite is a phosphate mineral with the formula Ca3Al7(SiO4)3(PO4)4(OH)3·16.5(H2O). It occurs in rare isolated masses in amblygonite-rich pegmatite deposits throughout the world. It was discovered in platy sheed form of 1mm hexagonal crystals. It was first described in 1977 by P.J. Dunn and D.E. Appleman from pegmatite collected from Bell Pit, Newry, Maine. Other specimens have been found in Kapunda, South Australia, in Silver Coin mine near Humboldt County, Nevada and various locations throughout Europe.
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- Perhamite-181540.jpg
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- IMA Mineral Symbol
- Phm
- chemical formula
- Ca₃Al₇.₇Si₃P₄O₂₃.₅(OH)₁₄.₁ · 8H₂O
- Nickel-Strunz '10th ed', review of (9th ed/ 2009 update)
- 8.DO.20
- Commons category
- Perhamite
- Nickel-Strunz 9th edition (updated 2009)
- 8.DO.20
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Article
5 sectionsContents
- Composition
- Physical properties
- Origin of the name
- See also
- References
Perhamite is a phosphate mineral with the formula Ca3Al7(SiO4)3(PO4)4(OH)3·16.5(H2O). It occurs in rare isolated masses in amblygonite-rich pegmatite deposits throughout the world. It was discovered in platy sheed form of 1mm hexagonal crystals. It was first described in 1977 by P.J. Dunn and D.E. Appleman from pegmatite collected from Bell Pit, Newry, Maine. Other specimens have been found in Kapunda, South Australia, in Silver Coin mine near Humboldt County, Nevada and various locations throughout Europe.
==Composition== The formula Ca3Al7(SiO4)3(PO4)4(OH)3·16.5(H2O) was determined by measuring its composition with x-ray spectroscopy giving the average amounts of SiO2 to be 13.72%, Al2O3 to be 27.17%, CaO to be 12.81%, P2O5 to be 21.61%, leaving 24.69% to be determined as H2O. The formula's essential elements are Al, Ca, H, O, P and Si with trace amounts of Sr. Common impurities of perhamite include Ti, Fe, Mg, Na, and F.