Otwayite, Ni₂CO₃(OH)₂, is a hydrated

nickel Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow to ...

carbonate mineral Carbonate minerals are those minerals containing the carbonate ion, . Carbonate divisions Anhydrous carbonates *Calcite group: trigonal **Calcite CaCO3 **Gaspéite (Ni,Mg,Fe2+)CO3 **Magnesite MgCO3 **Otavite CdCO3 **Rhodochrosite MnCO3 **Sider ...

. Otwayite is green, with a

hardness In materials science, hardness (antonym: softness) is a measure of the resistance to localized plastic deformation induced by either mechanical indentation or abrasion. In general, different materials differ in their hardness; for example hard ...

of 4, a specific gravity of 3.4, and crystallises in the

orthorhombic In crystallography, the orthorhombic crystal system is one of the 7 crystal systems. 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 r ...

system.

Occurrence

Otwayite is found in association with nullaginite and

hellyerite {{infobox mineral , name = Hellyerite , image = Hellyerite-Heazlewoodite-Zaratite-255032.jpg , imagesize = 260px , alt = , caption = Zaratite (emerald-green coating), hellyerite (powder-blue) and heazlewoodite (light b ...

in the Otway nickel deposit. It is found in association with theoprastite, hellyerite, gaspeite and a suite of other nickel carbonate minerals in the Lord Brassey Mine,

Tasmania ) , nickname = , image_map = Tasmania in Australia.svg , map_caption = Location of Tasmania in AustraliaCoordinates: , subdivision_type = Country , subdi ...

. Otwayite is found in association with gaspeite, hellyerite and

kambaldaite Kambaldaite, NaNi4(CO3)3(OH)3·3H2O, is an extremely rare hydrated sodium nickel carbonate mineral described from gossanous material associated with Kambalda type komatiitic nickel ore deposits at Kambalda, Western Australia, and Widgie Townsite n ...

in the Widgie Townsite nickel

gossan Gossan (eiserner hut or eisenhut) is intensely oxidized, weathered or decomposed rock, usually the upper and exposed part of an ore deposit or mineral vein. In the ''classic'' gossan or iron cap all that remains is iron oxides and quartz, often i ...

, Widgiemooltha,

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

. It is also reported from the Pafuri nickel deposit,

South Africa South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. It is bounded to the south by of coastline that stretch along the South Atlantic and Indian Oceans; to the north by the neighbouring countri ...

. It was first described in 1977 from the Otway Nickel Deposit, Nullagine,

Pilbara Craton The Pilbara Craton is an old and stable part of the continental lithosphere located in the Pilbara region of Western Australia. The Pilbara Craton is one of only two pristine Archaean 3.6–2.7 Ga (billion years ago) crusts identified on the ...

and named for Australian prospector Charles Albert Otway (born 1922).

References

* * * Henry, D. A. & Birch, W. D. (1992): Otwayite and theophrastite from the Lord Brassey Mine, Tasmania. Mineral. Mag. 56, 252-255. * Andersen, P., Bottrill, R. & Davidson, P. (2002): Famous mineral localities: The Lord Brassey mine, Tasmania. Mineral. Rec. 33, 321-332. Nickel minerals Carbonate minerals Orthorhombic minerals {{carbonate-mineral-stub