Perhamite
Encyclopedia
Perhamite is a phosphate
mineral
with the formula Ca
3Al
7(SiO4)3(P
O
4)4(OH)3·16.5(H2O
).
It occurs in rare isolated masses in amblygonite
-rich pegmatite
deposits throughout the world. It was discovered in 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 specimines have been found in Kapunda, South Australia, in Silver Coin mine near Humboldt County, Nevada
and various locations throughout Europe.
3Al
7(SiO4)3(P
O
4)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
.
who is currently part of the faculty of The Maine Pegmatite Workshop and has over 45 years experience in mining pegmatites
Phosphate
A phosphate, an inorganic chemical, is a salt of phosphoric acid. In organic chemistry, a phosphate, or organophosphate, is an ester of phosphoric acid. Organic phosphates are important in biochemistry and biogeochemistry or ecology. Inorganic phosphates are mined to obtain phosphorus for use in...
mineral
Mineral
A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...
with the formula Ca
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
3Al
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
7(SiO4)3(P
Phosphorus
Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...
O
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
4)4(OH)3·16.5(H2O
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
).
It occurs in rare isolated masses in amblygonite
Amblygonite
Amblygonite is a fluorophosphate mineral, AlPO4, composed of lithium, sodium, aluminium, phosphate, fluoride and hydroxide. The mineral occurs in pegmatite deposits and is easily mistaken for albite and other feldspars. Its density, cleavage and flame test for lithium are diagnostic. Amblygonite...
-rich pegmatite
Pegmatite
A pegmatite is a very crystalline, intrusive igneous rock composed of interlocking crystals usually larger than 2.5 cm in size; such rocks are referred to as pegmatitic....
deposits throughout the world. It was discovered in in platy sheed form of 1mm hexagonal crystals. It was first described in 1977 by P.J. Dunn and D.E.Appleman from pegmatite
Pegmatite
A pegmatite is a very crystalline, intrusive igneous rock composed of interlocking crystals usually larger than 2.5 cm in size; such rocks are referred to as pegmatitic....
collected from Bell Pit, Newry, Maine
Newry, Maine
Newry is a town in Oxford County, Maine, United States. The population was 344 at the 2000 census. Newry is the home of Sunday River Ski Resort and has a proportionately large seasonal population.-History:...
.Other specimines have been found in Kapunda, South Australia, in Silver Coin mine near Humboldt County, Nevada
Humboldt County, Nevada
Humboldt County is a county located in the U.S. state of Nevada. As of 2007, the population was estimated to be 18,052. Its county seat is Winnemucca.The county was the site of an arrest in 2000 that led to the U.S. Supreme Court decision Hiibel v...
and various locations throughout Europe.
Composition
The formula CaCalcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
3Al
Aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....
7(SiO4)3(P
Phosphorus
Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...
O
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
4)4(OH)3·16.5(H2O
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
) 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
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
The formula's essential elements are Al, Ca
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
, H
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...
, O
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
, P and Si
Silicon
Silicon is a chemical element with the symbol Si and atomic number 14. A tetravalent metalloid, it is less reactive than its chemical analog carbon, the nonmetal directly above it in the periodic table, but more reactive than germanium, the metalloid directly below it in the table...
with trace amounts of Sr
Strontium
Strontium is a chemical element with the symbol Sr and the atomic number 38. An alkaline earth metal, strontium is a soft silver-white or yellowish metallic element that is highly reactive chemically. The metal turns yellow when exposed to air. It occurs naturally in the minerals celestine and...
. Common impurities of perhamite include Ti
Titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....
,Fe
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
,Mg
Magnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
, Na
Sodium
Sodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...
, and F
Fluorine
Fluorine is the chemical element with atomic number 9, represented by the symbol F. It is the lightest element of the halogen column of the periodic table and has a single stable isotope, fluorine-19. At standard pressure and temperature, fluorine is a pale yellow gas composed of diatomic...
.
Physical Properties
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 IangreyiteOrigin of the Name
Perhamite is named after Frank Croydon Perham (1934-present), an American geologist and pegmatite miner of West Paris, MaineWest Paris, Maine
West Paris is a town in Oxford County, Maine, United States. The population was 1,722 at the 2000 census.-History:It began as part of Paris, granted by the Massachusetts General Court in 1771 to Captain Joshua Fuller and his company of 64 soldiers as payment for their service to the colony...
who is currently part of the faculty of The Maine Pegmatite Workshop and has over 45 years experience in mining pegmatites