Perhamite
A variety of Minerals
What is Perhamite?
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.
Market Value Factors
Pricing varies for every rock and mineral, so use these universal factors to gauge Perhamite before comparing listings or appraisals.
Size & Weight
Larger, intact specimens usually command higher prices.
Rarity & Demand
Scarce material or popular varieties sell at a premium.
Condition & Finish
Chips, repairs, and heavy wear lower value; clean prep helps.
Treatment & Provenance
Untreated specimens with documented locality are prized.
Perhamite Localities Map
See where Perhamite is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.
Key Characteristics
Characteristics of Perhamite
Perhamite can range in color from white to brown and can be translucent to opaque. Its luster is said to be earthy, but vitreous to pearly along fractures. It occurs as radial discoidal, platy hexagonal crystals, in rough spherules up to 1mm thick. The specific gravity of perhamite is measured at 2.64 with a calculated density of 2.53. It is structurally related to minerals in the crandallite subgroup, namely Iangreyite.
Composition of Perhamite
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.
Quick Facts
Physical Properties
- Color
- Colourless, white, light brown, orange
- Hardness (Mohs)
- 5
- Density
- 2.53 g/cm³
- Streak
- white
Chemical Properties
- Chemical Formula
- Ca3Al7.7Si3P4O23.5(OH)14.1 · 8H2O
- Elements
- Al, Ca, H, O, P, Si
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Perhamite FAQs
How do I identify Perhamite?
Perhamite can be identified by its hardness of 5 on the Mohs scale, Colourless color. Look for these key characteristics when examining specimens.
What color is Perhamite?
Perhamite typically appears in Colourless, white, light brown, orange. Color can vary depending on impurities and formation conditions.
How hard is Perhamite?
Perhamite has a hardness of 5 on the Mohs scale. This gives it moderate hardness.
What is the characteristics of perhamite of Perhamite?
Perhamite can range in color from white to brown and can be translucent to opaque. Its luster is said to be earthy, but vitreous to pearly along fractures. It occurs as radial discoidal, platy hexagonal crystals, in rough spherules up to 1mm thick. The specific gravity of perhamite is measured at 2.64 with a calculated density of 2.53. It is structurally related to minerals in the crandallite subgroup, namely Iangreyite.
What is the composition of perhamite of Perhamite?
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.
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