Collinsite is a mineral with chemical formula . It was discovered in

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...

, Canada, and formally described in 1927. It was named in honor of William Henry Collins (1878–1937), director of the

Geological Survey of Canada The Geological Survey of Canada (GSC; french: Commission géologique du Canada (CGC)) is a Canadian federal government agency responsible for performing geological surveys of the country, developing Canada's natural resources and protecting the e ...

. There are three varieties of the mineral: magnesian collinsite,

zinc Zinc is a chemical element with the symbol Zn and atomic number 30. Zinc is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodi ...

ian collinsite, and

strontian Strontian (; gd, Sròn an t-Sìthein) is the main village in Sunart, an area in western Lochaber, Highland, Scotland, on the A861 road. Prior to 1975 it was part of Argyllshire. It lies on the north shore of Loch Sunart, close to the head of ...

collinsite. The

crystal structure In crystallography, crystal structure is a description of the ordered arrangement of atoms, ions or molecules in a crystalline material. Ordered structures occur from the intrinsic nature of the constituent particles to form symmetric patterns ...

consists of polyhedral chains linked by weak hydrogen bonds.

Description

Collinsite is translucent and brown, chocolate-black, light brown, yellowish white, white, or colorless. It is colorless in

thin section In optical mineralogy and petrography, a thin section (or petrographic thin section) is a thin slice of a rock or mineral sample, prepared in a laboratory, for use with a polarizing petrographic microscope, electron microscope and electron ...

and light yellow-brown to colorless in

transmitted light Transmittance of the surface of a material is its effectiveness in transmitting radiant energy. It is the fraction of incident electromagnetic power that is transmitted through a sample, in contrast to the transmission coefficient, which is th ...

. The zincian variety of collinsite is pale blue. The mineral can occur with fibrous

habit A habit (or wont as a humorous and formal term) is a routine of behavior that is repeated regularly and tends to occur subconsciously.

, as globular aggregates of crystals, as concentrically layered

botryoidal A botryoidal ( ) texture or mineral habit, is one in which the mineral has an external form composed of many rounded segments, named for the Ancient Greek (), meaning "a bunch of grapes".Adjective form: ''botruoeidēs'' This is a common form f ...

masses, or as bladed or prismatic crystals up to . Collinsite is a member of the fairfieldite group. Hillite is the zinc analogue of collinsite and collinsite is the magnesium analogue of messelite.

Varieties

There are three varieties of collinsite: *magnesian collinsite, *zincian collinsite, *strontian collinsite, } Magnesian collinsite was described from South Dakota in 1972, zincian collinsite was described from South Australia in 1973, and strontian collinsite was described from Russia as early as 1965. The replacement of calcium by strontium that occurs in strontian collinsite is atypical of collinsite.

Structure

The

of collinsite was determined using essentially pure magnesian collinsite, Ca₂Mg(PO₄)₂·2H₂O, and published in 1974. It consists of chains of corner-sharing (MgΦ₆) octahedra and (PO₄) tetrahedra. Four of the Mg

ligand In coordination chemistry, a ligand is an ion or molecule ( functional group) that binds to a central metal atom to form a coordination complex. The bonding with the metal generally involves formal donation of one or more of the ligand's elec ...

s link to (PO₄) groups and the other two to water molecules. Two of the ligands in the (PO₄) group link to (MgΦ₆) octahedra and the other two link to calcium atoms and act as hydrogen bond acceptors. Weak hydrogen bonds link chains together and force separation between them. The separation gives room for interstitial, eight-coordinated calcium between chains.

History

Collinsite was discovered prior to 1927 near

François Lake François Lake in British Columbia is about south of Burns Lake and west of Fraser Lake. The lake is long, making it the second longest natural lake entirely within British Columbia after Babine Lake. Nadina River The Nadina River is a river ...

, British Columbia. In a , phosphorite nodules were discovered that consisted of a fragment of

andesite Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predo ...

enclosed by concentric layers of

phosphate mineral Phosphate minerals contain the tetrahedrally coordinated phosphate (PO43−) anion along sometimes with arsenate (AsO43−) and vanadate (VO43−) substitutions, and chloride (Cl−), fluoride (F−), and hydroxide (OH−) anions that also fit ...

s coated in

wurtzilite {{Short pages monitor