Whiteite
Encyclopedia
Whiteite is a rare hydrated phosphate
mineral, with hydroxyl
In the whiteite formulae, the symbols in brackets indicate the dominant atom in three distinct structural positions, designated X, M(1), and M(2), in that order; for instance, magnesium
Mg is always the dominant atom in the M(2) position for all the whiteite minerals.
Whiteite was named after John Sampson White Jr (1933-), associate curator of minerals at the Smithsonian Institution
, and founder, editor and publisher (1970-1982) of the Mineralogical Record.
with point group
2/m. Most sources give the space group
as P21/a for the Ca Fe rich member, which was the first of the series to be described , but Dana gives it as P2/a.
The other members are variously described in different sources as having space groups P21/a, P2/a or Pa.
There are two formula units per unit cell (Z = 2). The cell parameters vary slightly between the group members, but to the nearest angstrom
they all have a = 15 Å, b = 7 Å and c = 10 Å, with β 112.5 to 113.4. Individual values are :
and a white to brownish white streak
. They occur as aggregates of tabular crystals, or thick tabular canoe-shaped crystals. Whiteite from Rapid Creek in the Yukon
, Canada, is often associated with deep blue lazulite
crystals (33 out of 49 photos on Mindat
).
is thought to be biaxial (+)
, but whiteite-(CaFeMg) may be biaxial (-)
. The refractive indices are Nx = 1.580, Ny = 1.584 to 1.585 and Nz = 1.590 to 1.591, similar to those for quartz
.
, giving the crystals a pseudo-orthorhombic
appearance , and the cleavage
is good to perfect.
Whiteite is quite soft , with hardness 3 to 4, between calcite
and fluorite
. Its specific gravity
is 2.58, similar to that of quartz
. Whiteite is not radioactive .
for whiteite-(CaFeMg)and whiteite-(MnFeMg) is the Ilha claim, Taquaral
, Itinga, Jequitinhonha valley, Minas Gerais, Brazil, and for whiteite-(CaMnMg) it is the Tip Top Mine (Tip Top pegmatite), Fourmile, Custer District, Custer County, South Dakota
, USA. The type material is conserved at the National School of Mines
, Paris, France, and at the National Museum of Natural History
, Washington DC, USA, reference 123013.
At the Lavra da Ilha pegmatite
, Taquaral
, Brazil, whiteite is found in a complex zoned granite
pegmatite associated with eosphorite
, zanazziite
, wardite
, albite
and quartz
.
At Blow River, the Yukon
, Canada, it is found in iron-rich sedimentary rocks with siderite
, lazulite
, rrojadite] and quartz
.
At Ilha de Taquaral
, Minas Gerais, Brazil, it occurs along joints and fractures in quartz
and albite
associated with other phosphates.
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, with hydroxyl
Hydroxyl
A hydroxyl is a chemical group containing an oxygen atom covalently bonded with a hydrogen atom. In inorganic chemistry, the hydroxyl group is known as the hydroxide ion, and scientists and reference works generally use these different terms though they refer to the same chemical structure in...
Whiteite Subgroup
The name whiteite refers to three minerals in the jahnsite-whiteite group, whiteite subgroup. Subgroup members (formulae from IMA):- Whiteite-(CaFeMg), IMA1975-001, CaFe2+Mg2Al2(PO4)4(OH)2·8H2O
- Whiteite-(MnFeMg), IMA1978-A, Mn2+Fe2+Mg2Al2(PO4)4(OH)2·8H2O
- Whiteite-(CaMnMg), IMA1986-012, CaMn2+Mg2Al2(PO4)4(OH)2·8H2O
- Rittmannite, Mn2+Mn2+Fe2+2Al2(PO4)4(OH)2·8H2O
In the whiteite formulae, the symbols in brackets indicate the dominant atom in three distinct structural positions, designated X, M(1), and M(2), in that order; for instance, magnesium
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...
Mg is always the dominant atom in the M(2) position for all the whiteite minerals.
Whiteite was named after John Sampson White Jr (1933-), associate curator of minerals at the Smithsonian Institution
Smithsonian Institution
The Smithsonian Institution is an educational and research institute and associated museum complex, administered and funded by the government of the United States and by funds from its endowment, contributions, and profits from its retail operations, concessions, licensing activities, and magazines...
, and founder, editor and publisher (1970-1982) of the Mineralogical Record.
Unit Cell
All members of the series belong to the monoclinic crystal systemMonoclinic crystal system
In crystallography, the monoclinic crystal system is one of the 7 lattice point groups. A crystal system is described by three vectors. In the monoclinic system, the crystal is described by vectors of unequal length, as in the orthorhombic system. They form a rectangular prism with a...
with point group
Space group
In mathematics and geometry, a space group is a symmetry group, usually for three dimensions, that divides space into discrete repeatable domains.In three dimensions, there are 219 unique types, or counted as 230 if chiral copies are considered distinct...
2/m. Most sources give the space group
Space group
In mathematics and geometry, a space group is a symmetry group, usually for three dimensions, that divides space into discrete repeatable domains.In three dimensions, there are 219 unique types, or counted as 230 if chiral copies are considered distinct...
as P21/a for the Ca Fe rich member, which was the first of the series to be described , but Dana gives it as P2/a.
The other members are variously described in different sources as having space groups P21/a, P2/a or Pa.
There are two formula units per unit cell (Z = 2). The cell parameters vary slightly between the group members, but to the nearest angstrom
Ångström
The angstrom or ångström, is a unit of length equal to 1/10,000,000,000 of a meter . Its symbol is the Swedish letter Å....
they all have a = 15 Å, b = 7 Å and c = 10 Å, with β 112.5 to 113.4. Individual values are :
- Whiteite-(CaFeMg) a = 14.90 Å, b = 6.98 Å, c = 10.13 Å, β = 113.12
- Whiteite-(MnFeMg) a = 14.99 Å, b = 6.96 Å, c = 10.14 Å, β = 113.32
- Whiteite-(CaMnMg) a = 14.842 Å, b = 6.976 Å, c = 10.109 Å, β = 112.59
Appearance
The whiteite minerals are generally brown, pink or yellow, and whiteite-(CaMnMg) may also be light lavender coloured. They are transparent to translucent, with a vitreous lusterLustre (mineralogy)
Lustre is a description of the way light interacts with the surface of a crystal, rock, or mineral. The word lustre traces its origins back to the Latin word lux, meaning "light", and generally implies radiance, gloss, or brilliance....
and a white to brownish white streak
Streak (mineralogy)
The streak of a mineral is the color of the powder produced when it is dragged across an unweathered surface. Unlike the apparent color of a mineral, which for most minerals can vary considerably, the trail of finely ground powder generally has a more consistent characteristic color, and is thus...
. They occur as aggregates of tabular crystals, or thick tabular canoe-shaped crystals. Whiteite from Rapid Creek in the Yukon
Yukon
Yukon is the westernmost and smallest of Canada's three federal territories. It was named after the Yukon River. The word Yukon means "Great River" in Gwich’in....
, Canada, is often associated with deep blue lazulite
Lazulite
Lazulite is a blue, phosphate-based mineral containing magnesium, iron, and aluminium phosphate. Lazulite forms one endmember of a solid solution series with the darker iron rich scorzalite....
crystals (33 out of 49 photos on Mindat
Mindat
Mindat may refer to several places in Burma:*Mindat, Chin State, in Burma*Mindat Township, in Burma*Mindat District in Chin State, Burma*Mindat, Magway State in Minhla*Mindat, Yebyu, Tanintharyi Division*Mindat, Thayetchaung, Tanintharyi Division...
).
Optical Properties
The optical classBirefringence
Birefringence, or double refraction, is the decomposition of a ray of light into two rays when it passes through certain anisotropic materials, such as crystals of calcite or boron nitride. The effect was first described by the Danish scientist Rasmus Bartholin in 1669, who saw it in calcite...
is thought to be biaxial (+)
Birefringence
Birefringence, or double refraction, is the decomposition of a ray of light into two rays when it passes through certain anisotropic materials, such as crystals of calcite or boron nitride. The effect was first described by the Danish scientist Rasmus Bartholin in 1669, who saw it in calcite...
, but whiteite-(CaFeMg) may be biaxial (-)
Birefringence
Birefringence, or double refraction, is the decomposition of a ray of light into two rays when it passes through certain anisotropic materials, such as crystals of calcite or boron nitride. The effect was first described by the Danish scientist Rasmus Bartholin in 1669, who saw it in calcite...
. The refractive indices are Nx = 1.580, Ny = 1.584 to 1.585 and Nz = 1.590 to 1.591, similar to those for quartz
Quartz
Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...
.
Physical Properties
Whiteite is invariably twinnedCrystal twinning
Crystal twinning occurs when two separate crystals share some of the same crystal lattice points in a symmetrical manner. The result is an intergrowth of two separate crystals in a variety of specific configurations. A twin boundary or composition surface separates the two crystals....
, giving the crystals a pseudo-orthorhombic
Orthorhombic crystal system
In crystallography, the orthorhombic crystal system is one of the seven lattice point groups. Orthorhombic lattices result from stretching a cubic lattice along two of its orthogonal pairs by two different factors, resulting in a rectangular prism with a rectangular base and height , such that a,...
appearance , and the cleavage
Cleavage (crystal)
Cleavage, in mineralogy, is the tendency of crystalline materials to split along definite crystallographic structural planes. These planes of relative weakness are a result of the regular locations of atoms and ions in the crystal, which create smooth repeating surfaces that are visible both in the...
is good to perfect.
Whiteite is quite soft , with hardness 3 to 4, between calcite
Calcite
Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate . The other polymorphs are the minerals aragonite and vaterite. Aragonite will change to calcite at 380-470°C, and vaterite is even less stable.-Properties:...
and fluorite
Fluorite
Fluorite is a halide mineral composed of calcium fluoride, CaF2. It is an isometric mineral with a cubic habit, though octahedral and more complex isometric forms are not uncommon...
. Its specific gravity
Specific gravity
Specific gravity is the ratio of the density of a substance to the density of a reference substance. Apparent specific gravity is the ratio of the weight of a volume of the substance to the weight of an equal volume of the reference substance. The reference substance is nearly always water for...
is 2.58, similar to that of quartz
Quartz
Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...
. Whiteite is not radioactive .
Occurrence
The type localityType locality (geology)
Type locality , also called type area or type locale, is the where a particular rock type, stratigraphic unit, fossil or mineral species is first identified....
for whiteite-(CaFeMg)and whiteite-(MnFeMg) is the Ilha claim, Taquaral
Taquaral
Taquaral is a municipality in the state of São Paulo in Brazil. The population in 2004 was 2,867 and the area is 54.42 km². The elevation is 639 m....
, Itinga, Jequitinhonha valley, Minas Gerais, Brazil, and for whiteite-(CaMnMg) it is the Tip Top Mine (Tip Top pegmatite), Fourmile, Custer District, Custer County, South Dakota
Custer County, South Dakota
As of the census of 2000, there were 7,275 people, 2,970 households, and 2,067 families residing in the county. The population density was 5 people per square mile . There were 3,624 housing units at an average density of 2 per square mile...
, USA. The type material is conserved at the National School of Mines
École nationale supérieure des mines de Paris
The École Nationale Supérieure des Mines de Paris was created in 1783 by King Louis XVI in order to train intelligent directors of mines. It is one of the most prominent French engineering schoolsThe École Nationale Supérieure des Mines de Paris (also known as Mines ParisTech, École des Mines de...
, Paris, France, and at the National Museum of Natural History
National Museum of Natural History
The National Museum of Natural History is a natural history museum administered by the Smithsonian Institution, located on the National Mall in Washington, D.C., United States. Admission is free and the museum is open 364 days a year....
, Washington DC, USA, reference 123013.
At the Lavra da Ilha 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....
, Taquaral
Taquaral
Taquaral is a municipality in the state of São Paulo in Brazil. The population in 2004 was 2,867 and the area is 54.42 km². The elevation is 639 m....
, Brazil, whiteite is found in a complex zoned granite
Granite
Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...
pegmatite associated with eosphorite
Eosphorite
Eosphorite is a pink manganese phosphate mineral with chemical formula: MnAl2·H2O.Eosphorite crystallizes in the monoclinic crystal system. It forms prismatic crystals which often form radiating or spherical clusters...
, zanazziite
Zanazziite
Zanazziite is a mineral, a complex phosphate with the formula Ca24Be446·6H2O. Discovered in 1990 in Brazil, it is named after P. F. Zanazzi, Professor of Mineralogy, Perugia, Italy. Its color is pale to dark olive-green.-See also:...
, wardite
Wardite
Wardite is a hydrous sodium aluminium phosphate hydroxide mineral with formula: NaAl324·2. Wardite is of interest for its rare crystallography. It crystallizes in the tetragonal trapezohedral class and is one of only a few minerals in that class. Wardite forms vitreous green to bluish green to...
, albite
Albite
Albite is a plagioclase feldspar mineral. It is the sodium endmember of the plagioclase solid solution series. As such it represents a plagioclase with less than 10% anorthite content. The pure albite endmember has the formula NaAlSi3O8. It is a tectosilicate. Its color is usually pure white, hence...
and quartz
Quartz
Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...
.
At Blow River, the Yukon
Yukon
Yukon is the westernmost and smallest of Canada's three federal territories. It was named after the Yukon River. The word Yukon means "Great River" in Gwich’in....
, Canada, it is found in iron-rich sedimentary rocks with siderite
Siderite
Siderite is a mineral composed of iron carbonate FeCO3. It takes its name from the Greek word σίδηρος sideros, “iron”. It is a valuable iron mineral, since it is 48% iron and contains no sulfur or phosphorus...
, lazulite
Lazulite
Lazulite is a blue, phosphate-based mineral containing magnesium, iron, and aluminium phosphate. Lazulite forms one endmember of a solid solution series with the darker iron rich scorzalite....
, rrojadite] and quartz
Quartz
Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...
.
At Ilha de Taquaral
Taquaral
Taquaral is a municipality in the state of São Paulo in Brazil. The population in 2004 was 2,867 and the area is 54.42 km². The elevation is 639 m....
, Minas Gerais, Brazil, it occurs along joints and fractures in quartz
Quartz
Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...
and albite
Albite
Albite is a plagioclase feldspar mineral. It is the sodium endmember of the plagioclase solid solution series. As such it represents a plagioclase with less than 10% anorthite content. The pure albite endmember has the formula NaAlSi3O8. It is a tectosilicate. Its color is usually pure white, hence...
associated with other phosphates.