Annabergite is an

arsenate mineral Arsenate minerals usually refer to the naturally occurring orthoarsenates, possessing the (AsO4)3− anion group and, more rarely, other arsenates with anions like AsO3(OH)2− (also written HAsO42−) (example: pharmacolite Ca(AsO3OH).2H2O) or ( ...

consisting of a

hydrous In chemistry, a hydrate is a substance that contains water or its constituent elements. The chemical state of the water varies widely between different classes of hydrates, some of which were so labeled before their chemical structure was underst ...

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 ...

arsenate The arsenate ion is . An arsenate (compound) is any compound that contains this ion. Arsenates are salts or esters of arsenic acid. The arsenic atom in arsenate has a valency of 5 and is also known as pentavalent arsenic or As(V). Arsenate res ...

, Ni₃(AsO₄)₂·8H₂O, crystallizing in the

monoclinic In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic s ...

system and isomorphous with

vivianite Vivianite () is a hydrated iron phosphate mineral found in a number of geological environments. Small amounts of manganese Mn2+, magnesium Mg and calcium Ca may substitute for iron Fe2+ in the structure.Gaines et al (1997) Dana’s New Minera ...

and

erythrite Erythrite or red cobalt is a secondary hydrated cobalt arsenate mineral with the formula . Erythrite and annabergite, chemical formula , or nickel arsenate form a complete series with the general formula . Erythrite crystallizes in the monocli ...

. Crystals are minute and capillary and rarely met with, the mineral occurring usually as soft earthy masses and encrustations. A fine apple-green color is its characteristic feature. It was long known (since 1758) under the name nickel bloom; the name annabergite was proposed by H. J. Brooke and W H. Miller in 1852, from Annaberg in

Saxony Saxony (german: Sachsen ; Upper Saxon: ''Saggsn''; hsb, Sakska), officially the Free State of Saxony (german: Freistaat Sachsen, links=no ; Upper Saxon: ''Freischdaad Saggsn''; hsb, Swobodny stat Sakska, links=no), is a landlocked state of ...

, one of the localities of the mineral. It occurs with ores of nickel, of which it is a product of alteration. A variety, from

Creetown Creetown (, sometimes ) is a small seaside town in the Stewartry of Kirkcudbright, in Galloway in the Dumfries and Galloway council area in south-west Scotland. Its population is about 750 people. It is situated near the head of Wigtown Bay, ...

Kirkcudbrightshire Kirkcudbrightshire ( ), or the County of Kirkcudbright or the Stewartry of Kirkcudbright is one of the historic counties of Scotland, covering an area in the south-west of the country. Until 1975, Kirkcudbrightshire was an administrative count ...

, in which a portion of the nickel is replaced by

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar t ...

, has been called ''dudgeonite'', after P. Dudgeon, who found it. Closely related is ''cabrerite'' wherein some of the nickel is replaced by magnesium. It is named for Sierra Cabrera in

Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , i ...

where it was originally found.

References

Arsenate minerals Nickel minerals Monoclinic minerals Minerals in space group 12 Vivianite group {{mineral-stub