Minyulite
Encyclopedia
Minyulite is a rare phosphate mineral with a chemical formula of KAl2(OH,F)(PO4)2·4(H2O).
It occurs as groups of radiating fine fibrous crystals within rock cracks of phosphatic ironstone
. Minyulite belongs to the orthorhombic crystal system. This indicates that it has three axes of unequal length yet all are perpendicular to each other. It's cell constants are a=9.35, b=9.74 c=5.52.
As for its optical properties, Minyulite is an anisotropic mineral which means the velocity of light differs when traveling through it depending on the cut of its cross section which gives it more than one refractive index. The mineral is optically biaxial. Its birefringence value is 0.007. It has three refractive indices which are nα=1.531 nβ=1.534 nγ=1.538. Refractive indices are a ratio of the speed of light in a median with respect to the speed of light passing through the mineral.
, Minyulo Well in Western Australia
.
Minyulite is considered as a secondary phosphate since it is formed by the alteration of a primary phosphate. It occurs in association with dufrenite, apatite
, fluellite
, wavellite
, variscite
and leucophosphite.
The mineral can be found in the underlying phosphatized rock zone of ornithogenic soil. Minyulite is not found in abundance, it can be found in the sea shore of the maritime Arctic.
It occurs as groups of radiating fine fibrous crystals within rock cracks of phosphatic ironstone
Ironstone
Ironstone is a sedimentary rock, either deposited directly as a ferruginous sediment or created by chemical repacement, that contains a substantial proportion of an iron compound from which iron either can be or once was smelted commercially. This term is customarily restricted to hard coarsely...
. Minyulite belongs to the orthorhombic crystal system. This indicates that it has three axes of unequal length yet all are perpendicular to each other. It's cell constants are a=9.35, b=9.74 c=5.52.
As for its optical properties, Minyulite is an anisotropic mineral which means the velocity of light differs when traveling through it depending on the cut of its cross section which gives it more than one refractive index. The mineral is optically biaxial. Its birefringence value is 0.007. It has three refractive indices which are nα=1.531 nβ=1.534 nγ=1.538. Refractive indices are a ratio of the speed of light in a median with respect to the speed of light passing through the mineral.
Occurrence
It was first described in 1933 for an occurrence in Western Australia and named after 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....
, Minyulo Well in Western Australia
Western Australia
Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...
.
Minyulite is considered as a secondary phosphate since it is formed by the alteration of a primary phosphate. It occurs in association with dufrenite, apatite
Apatite
Apatite is a group of phosphate minerals, usually referring to hydroxylapatite, fluorapatite, chlorapatite and bromapatite, named for high concentrations of OH−, F−, Cl− or Br− ions, respectively, in the crystal...
, fluellite
Fluellite
Fluellite is a mineral with the chemical formula Al2F2•7H2O. The name is from its chemical composition, being a fluate of alumine ....
, wavellite
Wavellite
Wavellite is a phosphate mineral with formula Al323·5H2O.It normally occurs as translucent green radial or spherical clusters.-Discovery and occurrence:...
, variscite
Variscite
Variscite is a hydrated aluminium phosphate mineral |H2O]]). It is a relatively rare phosphate mineral. It is sometimes confused with turquoise; however, variscite is usually greener in color....
and leucophosphite.
The mineral can be found in the underlying phosphatized rock zone of ornithogenic soil. Minyulite is not found in abundance, it can be found in the sea shore of the maritime Arctic.