Woodhouseite
Encyclopedia
Woodhouseite belongs to the beudantite group AB3(XO4)(SO4)(OH)6 where A = Ba, Ca, Pb or Sr, B = Al or Fe and X = S, As or P. Minerals in this group are isostructural with each other and also with minerals in the crandallite and alunite
Alunite
Alunite is a sulfate mineral that was first observed in the 15th century in Monti della Tolfa, north of Rome, where it was mined for the manufacture of alum. First called aluminilite by J.C. Delamétherie in 1797, this name was contracted by François Beudant in 1824 to alunite.Distinct crystals of...

 groups. They crystallise in the rhombohedral system with 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...

 Rm and crystals are usually either tabular {0001} or pseudo-cubic to pseudo-cuboctahedral.
Woodhouseite was named after Professor Charles Douglas Woodhouse (1888–1975), an American mineralogist and mineral collector from the University of California, Santa Barbara, USA, and one-time General Manager of Champion Sillimanite, Inc.

Environment

Woodhouseite is a secondary mineral found where wall rock
Wall rock
Wall rock is the rock that constitutes the wall of an area undergoing geologic activity. Examples are the rock along the neck of a volcano, on the edge of a pluton that is being emplaced, along a fault plane, enclosing a mineral deposit, or where a vein or dike is being emplaced.In volcanoes, wall...

 alteration occurred in hydrothermal and disseminated ore deposits; rare in cave deposits, formed from guano
Guano
Guano is the excrement of seabirds, cave dwelling bats, and seals. Guano manure is an effective fertilizer due to its high levels of phosphorus and nitrogen and also its lack of odor. It was an important source of nitrates for gunpowder...

. At the type locality it occurs in vugs in quartz veins in an andalusite
Andalusite
Andalusite is an aluminium nesosilicate mineral with the chemical formula Al2SiO5.The variety chiastolite commonly contains dark inclusions of carbon or clay which form a checker-board pattern when shown in cross-section....

, Al2OSiO4, deposit. This is in pre-Cambrian meta-quartzite that has been intruded by late Jurassic
Jurassic
The Jurassic is a geologic period and system that extends from about Mya to  Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...

 granitic rocks. Woodhouseite is found only near masses of 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....

, MgAl2(PO4)2(OH)2.
Associated Minerals at the type locality include topaz
Topaz
Topaz is a silicate mineral of aluminium and fluorine with the chemical formula Al2SiO42. Topaz crystallizes in the orthorhombic system and its crystals are mostly prismatic terminated by pyramidal and other faces.-Color and varieties:...

, Al2SiO4F2, 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,...

, SiO2, augelite
Augelite
Augelite is an aluminium phosphate mineral with formula: Al23. The shade varies from colorless to white, yellow or rose. Its crystal system is monoclinic....

, Al2PO4(OH)3, lazulite, MgAl2(PO4)2(OH)2, tourmaline
Tourmaline
Tourmaline is a crystal boron silicate mineral compounded with elements such as aluminium, iron, magnesium, sodium, lithium, or potassium. Tourmaline is classified as a semi-precious stone and the gem comes in a wide variety of colors...

, baryte, BaSO4, muscovite
Muscovite
Muscovite is a phyllosilicate mineral of aluminium and potassium with formula KAl22, or 236. It has a highly-perfect basal cleavage yielding remarkably-thin laminæ which are often highly elastic...

, KAl2(Si3Al)O10(OH)2, and pyrophyllite
Pyrophyllite
Pyrophyllite is a phyllosilicate mineral composed of aluminium silicate hydroxide: Al2Si4O102. It occurs in two more or less distinct varieties, namely, as crystalline folia and as compact masses; distinct crystals are not known....

, Al2Si4O10(OH)2, all of which formed before the woodhouseite, which is a late-forming mineral.

Localities

The type locality
Type 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....

 is the Champion Mine (White Mountain Mine), White Mountain, Laws, White Mountains
White Mountains (California)
The White Mountains of California are a triangular fault block mountain range facing the Sierra Nevada across the upper Owens Valley. They extend for approximately as a greatly elevated plateau about wide on the south, narrowing to a point at the north, with elevations generally increasing...

, Mono County, California
Mono County, California
Mono County is a county located in the east central portion of the U.S. state of California, to the east of the Sierra Nevada between Yosemite National Park and Nevada. As of the 2010 census, the population was 14,202, up from 12,853 at the 2000 census...

, USA. This is a former sillimanite
Sillimanite
Sillimanite is an alumino-silicate mineral with the chemical formula Al2SiO5. Sillimanite is named after the American chemist Benjamin Silliman . It was first described in 1824 for an occurrence in Chester, Middlesex County, Connecticut, USA....

 mine located near Laws; mineralisation is a metamorphic
Metamorphism
Metamorphism is the solid-state recrystallization of pre-existing rocks due to changes in physical and chemical conditions, primarily heat, pressure, and the introduction of chemically active fluids. Mineralogical, chemical and crystallographic changes can occur during this process...

 sillimanite deposit hosted in quartzite
Quartzite
Quartzite is a hard metamorphic rock which was originally sandstone. Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts. Pure quartzite is usually white to gray, though quartzites often occur in various shades of pink...

.

Structure

Space Group: R 2/m

Unit Cell Parameters: a = 6.993 Å, c = 16.386 Å, Z: 3
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