Aurichalcite
| Aurichalcite | |
|---|---|
 |
|
| General and classification | |
| chemical formula | (Zn, Cu) 5 [(OH) 6 | (CO 3 ) 2 ] |
|
Mineral class (and possibly department) |
Anhydrous carbonates with foreign anions |
|
System no. to Strunz and to Dana |
5.BA.15 ( 8th edition : V / C.01) 16a.04.02.01 |
| Similar minerals | Rosasite , smithsonite |
| Crystallographic Data | |
| Crystal system | monoclinic |
| Crystal class ; symbol | monoclinic prismatic 2 / m |
| Room group (no.) | P 2 1 / m (No. 11) |
| Lattice parameters |
a = 13.82 Å ; b = 6.42 Å; c = 5.29 Å β = 101.0 ° |
| Formula units | Z = 2 |
| Physical Properties | |
| Mohs hardness | 1 to 2 |
| Density (g / cm 3 ) | measured: 3.96; calculated: 3.93 to 3.94 |
| Cleavage | perfectly |
| Break ; Tenacity | leafy |
| colour | light green, teal, blue |
| Line color | blue green |
| transparency | translucent |
| shine | Silk to mother-of-pearl gloss |
| Crystal optics | |
| Refractive indices |
n α = 1.655 n β = 1.740 n γ = 1.744 |
| Birefringence | δ = 0.089 |
| Optical character | biaxial negative |
| Axis angle | 2V = measured: 1 to 4 °; calculated: 22 ° |
| Pleochroism | weak: X = colorless; Y = Z = blue-green |
| Other properties | |
| Chemical behavior | Soluble in acids with release of CO 2 |
Aurichalcite , out of date also known as brass blossom , copper zinc blossom , buratite , brassite , orichalcite or risseit , is a mineral from the mineral class of " carbonates ( and relatives )", which can be abundant in various locations, but is generally not very common. It crystallizes in the monoclinic crystal system with the chemical composition (Zn, Cu) 5 [(OH) 6 | (CO 3 ) 2 ] and develops mostly prismatic to needle-like crystals , but also encrustations.
Etymology and history
The mineral was first described in 1788 by Eugène Louis Melchior Patrin in the French magazine "Le Journal de physique et le radium" (Paris 33.81), who referred to it as calamine verdâtre .
The name Aurichalcit, which is still valid today, was not given until 1839 after the complete analysis by Theodor Boettger , who named it after the Greek word ὀρείχαλκος Oreichalkos (Latin for Aurichalkum ) for "Bergerz", that in general also for the name brass (alloy of copper and zinc ) was in use. Boettger chose this name based on the metals copper and zinc , which are predominant in the mineral, and which also make the alloy brass.
Aurichalcite was first discovered in the Loktevskoye (Loktevskii) mine on the Loktewka river (tributary of the Charysch ) in the Altaic Ore Mountains (Erz-Altai, Rudny Altai) in the Russian region of Western Siberia , which is also considered a type locality .
classification
In the meanwhile outdated, but still in use 8th edition of the mineral systematics according to Strunz , the aurichalcite belonged to the common mineral class of "carbonates, nitrates and borates " and there to the department of "anhydrous carbonates with foreign anions ", where together with azurite , brianyoungite , Georgeite , glaucosphere , hydrozincite , kolwezite , losyite , mcguinnessite , malachite , nullaginite , pokrovskite , rosasite , sclarite and zinc rosasite formed an independent group.
The 9th edition of Strunz's mineral systematics, which has been in force since 2001 and is used by the International Mineralogical Association (IMA), assigns aurichalcite to the class of "carbonates and nitrates" (the borates form an independent class here) and there in the department of " Carbonates without additional anions; without H 2 O “. However, this section is further subdivided according to the predominant metals in the compound or the chemical group to which they belong, so that the mineral can be found in the sub-section “With Cu, Co, Ni, Zn, Mg, Mn” according to its composition , where the "Aurichalcit-Hydrozinkitgruppe" with the system no. 5.BA.15 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the aurichalcite to the class of "carbonates, nitrates and borates" like the outdated Strunz'sche systematics, but there it is in the section "16a carbonates - hydroxyl or halogen". Here he is to be found as the only member of the unnamed group 16a.04.02 within the subsection “ Carbonates - Hydroxyl or Halogen with (AB) 5 (XO 3 ) 2 Z q ”.
Education and Locations
Aurichalcite is a secondary mineral that forms mainly under dry climatic conditions in the oxidation zone of copper and zinc deposits . It often occurs in small clusters of needle-shaped crystals fused with brown iron stone and calcite . Other accompanying minerals include azurite , hemimorphite , hydrozincite , linarite , malachite and wulfenite as well as rosasite and smithsonite , with which it can easily be confused due to the similarity of color and habit.
In total, Aurichalcite has so far (as of 2011) been detected at around 700 sites. In addition to its type locality Loktevskoye Mine on Loktewka in Siberia, the mineral was also found in Russia near Dalnegorsk in the Far Eastern Primorye region.
In Germany, the mineral occurred previously among others in several places in the Black Forest in Baden-Wuerttemberg, the Rudolfstein in Lichtenberg , Schmölz (Wallenfels) and at Rauschenberg in Bavaria in Richelsdorf and Langhecke in Hesse in Bramsche and at several locations in the resin in Lower Saxony; in several places in the Bergisches Land , in the Sauerland as well as in the Eifel and Siegerland from North Rhine-Westphalia to Rhineland-Palatinate and in the Ore Mountains in Saxony.
In Austria, Aurichalcite was found mainly in Carinthia , Salzburg , Styria and Tyrol, as well as near Annaberg in Lower Austria. In Switzerland, he has only performed in the Malcantone region and in several places in the canton of Valais .
Other locations include Argentina, Australia, Belgium, Bulgaria, Chile, China, the Democratic Republic of the Congo, France, Greece, Iran, Ireland, Italy, Japan, Canada, Kazakhstan, Madagascar, Morocco, Mexico, Namibia, New Caledonia, Norway , Poland, Portugal, Romania, Zambia, Slovakia, Slovenia, Spain, South Africa, Sweden, the Czech Republic, Turkey, Hungary, the United Kingdom (Great Britain), the United States (USA) and Vietnam.
Crystal structure
Aurichalcite crystallizes monoclinically in the space group P 2 1 / m (space group no. 11) with the lattice parameters a = 13.82 Å ; b = 6.42 Å; c = 5.29 Å and β = 101.0 ° and 2 formula units per unit cell .
See also
Individual evidence
- ↑ a b c d e Hugo Strunz , Ernest H. Nickel: Strunz Mineralogical Tables . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p. 295 .
- ↑ Webmineral - Aurichalcite (English)
- ↑ a b Handbook of Mineralogy - Aurichalcite (English, PDF 66 kB)
- ↑ a b c d e Aurichalcite at mindat.org (engl.)
- ↑ Mineral Atlas: Aurichalcite (Wiki)
- ↑ Theod. Boettger: Chemical investigation of aurichalcite, a new copper ore from the Altai , in: JC Poggendorff (Ed.): Annalen der Physik und Chemie , 8th and 40th volume, Leipzig 1839, p. 495 (PDF 311.4 kB)
- ↑ Mindat - Localities for Aurichalcite
literature
- Paul Ramdohr , Hugo Strunz : Klockmann's textbook of mineralogy . 16th edition. Ferdinand Enke Verlag, Stuttgart 1978, ISBN 3-432-82986-8 , p. 579 .
- Petr Korbel, Milan Novák: Encyclopedia of Minerals . Nebel Verlag GmbH, Eggolsheim 2002, ISBN 3-89555-076-0 , p. 123 ( Dörfler Natur ).
Web links
- Mineral Atlas: Aurichalcite (Wiki)