Cacoxenite

Cacoxenite is a rarely occurring mineral from the mineral class of " phosphates, arsenates and vanadates ." It crystallizes in the hexagonal crystal system with the chemical composition (Fe3 ) 24AlO6 ( PO4 ) 17 ( OH) 12 • 75 H2O and developed acicular to fibrous, often radial- mineral aggregates and crusty coatings from light yellow to brownish yellow or orange.

Etymology and history

Was first found in 1825 in Cacoxenite the " pit Hrbek " in St. Benigna ( Svatá Dobrotivá ) / Beroun in the Czech Republic and described by J. Steinmann, of the mineral by the Ancient Greek words κăκός " bad" for ζέυος and for " Guest", composed so " bad host " due to the fact that with Cacoxenite were blended iron ore and pig iron produced therefrom by increasing phosphorus content of lower quality.

Classification

In the old ( 8th edition ) and new classification of minerals according to Strunz ( 9th edition ) of the Cacoxenite belongs to the department of " hydrous phosphates with foreign anions ." The new Strunz'sche Mineral classification divided here but now more specific on the size of the cations and the molar ratio of the other anions for phosphate complex. The mineral is in accordance with the subdivision "With only medium-sized cations, (OH, etc.): RO 4 = 1: 1 and <2: 1".

The commonly used in English-speaking classification of minerals according to Dana assigns the Cacoxenite in the department of " hydrated phosphates, etc., with hydroxyl or halogen", where the mineral is found as the only member of the unnamed group " 42.13.5 ".

Education and Locations

Cacoxenite formed by hydrothermal processes in the clefts of sedimentary iron ores, but also as a secondary mineral weathering of primary phosphate minerals in granitic pegmatites. Accompanying minerals include Beraunite, Dufrénit, magnetite, Rockbridgeite, Strengit and Wavellite.

So far Cacoxenite could be detected in well 220 localities (as of 2009), as including in New South Wales, Queensland, South Australia and Victoria in Australia; Hainaut, Liège, Luxembourg and Namur in Belgium; Galiléia / Minas Gerais in Brazil; in the Rhodope Mountains in Bulgaria; in several regions of Germany and France; England and Wales in the United Kingdom; in County Limerick in Ireland; Piedmont and Sardinia in Italy; on Honshu in Japan; in the highlands of Adamawa in Cameroon; in Ontario, Canada; Durango in Mexico; in the Erongo Region of Namibia to the west; Salzburg and Styria in Austria; in the Portuguese districts Evora, Guarda, Viseu and Viana do Castelo; Lapland in Sweden; Banská Bystrica in Slovakia; in several regions of Spain; Bohemia and Moravia in the Czech Republic; in the Hungarian county Borsod -Abaúj -Zemplén; in the department of Artigas in Uruguay; as well as in many regions of the United States.

Crystal structure

Cacoxenite crystallized hexagonal space group P63 / m with lattice parameters a = 27,559 Å and c = 10.550 Å and two formula units per unit cell.