Waterhouseite, Mn₇(PO₄)₂(OH)₈, is a hydroxy

manganese Manganese is a chemical element; it has Symbol (chemistry), symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese was first isolated in the 1770s. It is a transition m ...

phosphate Phosphates are the naturally occurring form of the element phosphorus. In chemistry, a phosphate is an anion, salt, functional group or ester derived from a phosphoric acid. It most commonly means orthophosphate, a derivative of orthop ...

mineral. It is a medium-soft,

brittle A material is brittle if, when subjected to stress, it fractures with little elastic deformation and without significant plastic deformation. Brittle materials absorb relatively little energy prior to fracture, even those of high strength. ...

mineral occurring in pseudo-orthorhombic

monoclinic In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three Vector (geometric), vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in t ...

bladed crystals and orange-brown to dark brown in color. Waterhouseite is on the softer side with a

Mohs hardness The Mohs scale ( ) of mineral hardness is a qualitative ordinal scale, from 1 to 10, characterizing scratch resistance of mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid substance with a fair ...

of 4, has a

specific gravity Relative density, also called specific gravity, is a dimensionless quantity defined as the ratio of the density (mass of a unit volume) of a substance to the density of a given reference material. Specific gravity for solids and liquids is nea ...

of 3.5 and a yellowish-brown streak. It is named after

Frederick George Waterhouse Frederick George Waterhouse (25 August 1815 – 7 September 1898) was an English naturalist, zoologist and entomologist who made significant contributions to the study of the natural history of Australia. Waterhouse was born near London, a son ...

, first director of the South Australian Museum, as well as recognizes the work Waterhouse Club has done in support of the South Australian Museum.

Occurrence

Waterhouseite occurs in divergent sprays of bladed crystals up to 1mm in length and 20 micrometers in thickness. It is found in

South Australia South Australia (commonly abbreviated as SA) is a States and territories of Australia, state in the southern central part of Australia. With a total land area of , it is the fourth-largest of Australia's states and territories by area, which in ...

, specifically in the Iron Monarch mine,

Iron Knob Iron Knob is a town in the Australian state of South Australia on the Eyre Peninsula immediately south of the Eyre Highway. At the 2006 census, Iron Knob and the surrounding area had a population of 199. The town obtained its name from its prox ...

Middleback Range The Middleback Range is a mountain range on the eastern side of Eyre Peninsula in South Australia. The Middleback Range has been a source of iron ore for over a century, particularly to feed the Whyalla Steelworks. Mines in the region were first ...

Eyre Peninsula The Eyre Peninsula is a triangular peninsula in South Australia. It is bounded by the Spencer Gulf on the east, the Great Australian Bight on the west, and the Gawler Ranges to the north. Earlier called Eyre's Peninsula, it was named after e ...

, South Australia. Waterhouseite is generally found in a carbonate rich cavities with other minerals such as gatehouseite, seamanite,

rhodochrosite Rhodochrosite is a manganese carbonate mineral with chemical composition Manganese(II) carbonate, MnCO3. In its pure form (rare), it is typically a rose-red colour, but it can also be shades of pink to pale brown. It Streak (mineralogy), streak ...

shigaite Shigaite is a mineral with formula NaAl3(Mn2+)6(SO4)2(OH)18·12H2O that typically occurs as small, hexagonal crystals or thin coatings. It is named for Shiga Prefecture, Japan, where it was discovered in 1985. The formula was significantly revised ...

baryte Baryte, barite or barytes ( or ) is a mineral consisting of barium sulfate (Ba S O4). Baryte is generally white or colorless, and is the main source of the element barium. The ''baryte group'' consists of baryte, celestine (strontium sulfate), ...

hausmannite Hausmannite is a complex oxide, or a mixed oxide, of manganese containing both Divalent, di- and Trivalent, tri-valent manganese. Its chemical formula can be represented as , or more simply noted as , or , as commonly done for magnetite (), the co ...

and

hematite Hematite (), also spelled as haematite, is a common iron oxide compound with the formula, Fe2O3 and is widely found in rocks and soils. Hematite crystals belong to the rhombohedral lattice system which is designated the alpha polymorph of . ...

Crystal structure

Waterhouseite has a unique asymmetrical structure consisting of a dense, complex framework of Mn(O, OH)₆ octahedra and PO₄ tetrahedra which are linked by both edges and corners. It is highly unusual for the PO₄ tetrahedron to share two of its edges with the Mn(O, OH)₆ octahedral. There are only two other known arsenates that have the same edge sharing as waterhouseite.

References

External links

* http://rruff.info/doclib/cm/vol43/CM43_1401.pdf {{Authority control Manganese(II) minerals Phosphate minerals Hydroxide minerals Monoclinic minerals Minerals in space group 14

Occurrence

Crystal structure

See also

References

External links