Botryogen

Botryogen is a rarely occurring mineral from the mineral class of " sulfates, selenates, tellurates, chromates, molybdates and tungstates ," precisely, a hydrous magnesium iron sulfate with the chemical composition MgFe3 [ OH | (SO4 ) 2] • 7H2O.

Botryogen crystallizes in the monoclinic crystal system, and most developed prismatic crystals of striped orange-red color, whose crystal surfaces have vitreous luster. He can also be found in racemose and radialsrahligen mineral aggregates.

Etymology and history

Botryogen was first described in 1815 bear by Jöns Jakob Berzelius, who it βότρυς after the Greek words for wine grape and γευυăυ for so mutatis mutandis " grapes supporting" in relation to the racemose and stalaktitischen forms of training, such as those found in the type locality Falun in Sweden.

Classification

In the old ( 8th edition ) and new classification of minerals according to Strunz ( 9th edition ) of the Botryogen belongs to the department of the " water -containing sulfates with foreign anions ." Since the 9th edition of the Strunz'schen Mineral classification, this department is, however, precisely divided by the size of the involved cations and the crystal structure. The mineral is therefore now in accordance with the subdivision " with medium-sized cations and chains of edge- sharing octahedra ."

The classification of minerals according to Dana assigns the Botryogen in the class of sulfates ( and related compounds ), there however in the department of " hydrated sulfates with hydroxyl or halogen having the general formula (A B2 ) ( XO4 ) Zq • x (H2O) ".

Education and Locations

Botryogen is a typical secondary mineral that forms by oxidation of pyrite in arid climate conditions.

So far, the mineral could be detected at 38 localities (as of 2009), namely La Alcaparrosa (San Juan ) in Argentina; Mount Isa in Australia; the regions of Antofagasta and Tarapacá in Chile; Charbes in French Canton Villé; Rammelsberg and Ronneburg ( Thuringia) in Germany; Haji Abbad in the Iranian province of Hormozgan; the Italian regions of Liguria, Piedmont and Tuscany; Shikoku in Japan; Sillian in Austria; Falun in Sweden; Smolník in Slovakia; Minas de Riotinto in Spain; Balaklava in Ukraine; Rudabánya and Cserhát in the northern Hungarian Middle Mountains; and in Arizona, California, Nevada, Ohio, Pennsylvania, Tennessee and Utah in the United States.

Crystal structure

Botryogen crystallizes in the monoclinic crystal system, space group P21 / n with lattice parameters a = 10.51 Å, b = 17.85 Å, c = 7.14 Å and β = 100.00 °, and four formula units per unit cell.