Aurichalcite

Aurichalcit, outdated also known as brass flower, copper, zinc flower, Buratit, Messingit, Orichalcit or Risseit, is a mineral from the mineral class of " carbonates ( and relatives ) ," which can be in different localities partly abundant, but overall not very common. It crystallizes in the monoclinic crystal system with the chemical composition (Zn, Cu) 5 [( OH) 6 | (CO3 ) 2] and usually develops prismatic to acicular crystals, but also encrustations.

Etymology and history

Was first described in 1788 by Eugène Louis Melchior mineral Patrin in the French magazine " Le Journal de physique et le radium " (Paris 33.81 ), who described it as Calamine verdâtre.

His up today valid name Aurichalcit it was however only in 1839 after the complete analysis of Theodore Boettger, if, after the Greek word ὀρείχαλκος Oriharukon ( Latinized Aurichalkum ) for " Bergerz " notified that generally for the term brass (an alloy of copper and zinc ) was in use. Boettger chose this name based on the predominant mineral in the metals copper and zinc, which also result in the alloy brass.

Was first discovered in the Aurichalcit Loktevskoye ( Loktevskii ) mine on the river Loktewka ( tributary of the Charysh ) in the Altaic Erzgebirge ( Ore Altai, Altai Rudny ) in the Russian region of Western Siberia, which is also known as type locality.

Classification

In the now outdated but still in use 8th edition of the mineral classification by Strunz the Aurichalcit belonged to common mineral class of " carbonates, nitrates and borates " and then to the Department of " water clear carbonates with foreign anions ", where he, together with azurite, Brianyoungit, Georgeit, Glaukosphärit, hydrozincite, Kolwezit, Loseyit, McGuinnessit, malachite, Nullaginit, Pokrovskit, Rosasit, Sclarit and Zinkrosasit formed a distinct group.

The 9th edition used since 2001 and valid by the International Mineralogical Association ( IMC ) of the Strunz'schen Mineral classification assigns the Aurichalcit in the class of " carbonates and nitrates " ( here, the borates form a separate class) and then in the Department of " carbonates without further anions, without H2O ". This division, however, is further subdivided according to the conditions prevailing in the interconnect metals or chemical group to which they belong, so that the mineral according to its composition in the subsection "With Cu, Co, Ni, Zn, Mg, Mn " can be found where it only together with hydrozincite the " aurichalcite Hydrozinkitgruppe " with the system no. 5.BA.15 forms.

The mostly commonly used in English-speaking classification of minerals according to Dana assigns the Aurichalcit as the outdated Strunz'sche systematics in the class of " carbonates, nitrates and borates ", but there in the department " carbonates 16a - hydroxyl or halogen" one. Here he is the only member of the unnamed group 16a.04.02 within the subdivision " Carbonate - hydroxyl or halogen with (AB ) 5 ( XO3 ) 2ZQ " to find.

Education and Locations

Aurichalcit is a secondary mineral that is predominantly formed under dry climatic conditions in the oxidation zone of copper and zinc deposits. It often occurs in small clusters acicular crystals together with limonite and calcite intergrown. Other accompanying minerals include azurite, hemimorphite Hydrozincite, Linarit, malachite and Wulfenite and Rosasit and Smithsonite with which it can be easily confused due to the similarity of color and habit.

Overall, Aurichalcit so far (as of 2011) are detected at around 700 localities. Apart from its type locality Loktevskoye mine on Loktewka in Siberia, the mineral in Russia was still in Dalnegorsk in the Far Eastern Primorye.

In Germany the mineral previously occurred among others in several places in the Black Forest in Baden- Württemberg, at the Rudolf Stein, Lichtenberg, Schmölz (Wall rock) and on Rauschenberg in Bavaria, at Richelsdorf and Langhecke in Hesse, near Bramsche and at several places in the Harz Mountains in Lower Saxony; at several locations of the Bergisch Land, in the Sauerland and in the Eifel and the winning country of North Rhine -Westphalia Rhineland- Palatinate and up in the Ore Mountains in Saxony on.

In Austria Aurichalcit was found mainly in Carinthia, Salzburg, Styria and Tyrol and in Annaberg in Lower Austria. In Switzerland, he has so far only occurred in the Malcantone region and at several locations in the canton of Valais.

Other localities lie among others in Argentina, Australia, Belgium, Bulgaria, Chile, China, the Democratic Republic of Congo, France, Greece, Iran, Ireland, Italy, Japan, Kazakhstan, Madagascar, Mexico, Morocco, Namibia, New Caledonia, Norway, Poland, Portugal, Romania, Zambia, Slovakia, Slovenia, Spain, South Africa, Sweden, Czech Republic, Turkey, Hungary, the United Kingdom ( UK), the United States ( U.S.) and in Vietnam.

Crystal structure

Aurichalcit crystallizes in the monoclinic space group P21 / m ( Raumgruppen-Nr. 11) with the lattice parameters a = 13.82 Å; b = 6.42 Å; c = 5.29 Å and 101.0 ° and β = 2 formula units per unit cell.