Anchorite
| Anchorite | |
|---|---|
 |
|
| General and classification | |
| chemical formula | CaFe [CO 3 ] 2 |
|
Mineral class (and possibly department) |
Carbonates (and relatives), see classification |
|
System no. to Strunz and to Dana |
5.AB.10 ( 8th edition : V / B.03) 02/14/01/02 |
| Crystallographic Data | |
| Crystal system | trigonal |
| Crystal class ; symbol | rhombohedral 3 |
| Room group (no.) | R 3 (No. 148) |
| Lattice parameters | a = 4.84 Å ; c = 16.19 Å |
| Formula units | Z = 3 |
| Twinning | simple twins with the levels {0001}, {10 1 0} or {11 2 0} |
| Physical Properties | |
| Mohs hardness | 3.5 to 4 |
| Density (g / cm 3 ) | 2.95 to 3.10 |
| Cleavage | completely according to {10 1 1} |
| Break ; Tenacity | shell-like |
| colour | white, gray-brown, brown-yellow |
| Line color | White |
| transparency | transparent to translucent |
| shine | Glass gloss, pearlescent gloss |
| Crystal optics | |
| Refractive indices |
n ω = 1.690 to 1.750 n ε = 1.510 to 1.548 |
| Birefringence | δ = 0.180 to 0.202 |
| Optical character | uniaxial negative |
Anchorite ( brown spar ) is a frequently occurring mineral from the mineral class of anhydrous carbonates without foreign anions . It crystallizes in the trigonal crystal system with the chemical composition CaFe [CO 3 ] 2 and develops mostly rhombohedral crystals , but also granular aggregates in white, gray-brown or brown-yellow color with white streak color .
Anchorite forms a mixed series with dolomite (CaMg [CO 3 ] 2 ) and kutnohorite (CaMn [CO 3 ] 2 ).
Etymology and history
Anchorite was first discovered in Erzberg in Styria (Austria) and described in 1825 by Wilhelm Ritter von Haidinger , who named the mineral after the Austrian mineralogist Matthias Joseph Anker (1771–1843).
classification
In the meanwhile outdated, but still in use 8th edition of the mineral systematics according to Strunz , the anchorite belonged to the mineral class of "carbonates, nitrates and borates " and there to the department of "anhydrous carbonates without foreign anions ", where it belongs together with benstonite , dolomite , ewaldite , Huntite , kutnohorite , minrecordite and norsethite formed the "dolomite group".
The 9th edition of Strunz's mineral systematics, which has been valid since 2001 and is used by the International Mineralogical Association (IMA), assigns anchorite to the class of "carbonates and nitrates" (the borates form a separate class here) and there into the department of " Carbonates without additional anions; without H 2 O “. However, this section is further subdivided according to the type of cations involved , so that the mineral can be found according to its composition in the sub-section "alkaline earth (and other M 2+ ) carbonates", where it is only found together with dolomite, cutnohorite and minrecordite the "Dolomite Group" with the system no. 5.AB.10 forms.
The systematics of minerals according to Dana , like the outdated 8th edition of Strunz's systematics , assigns the anchorite to the common class of “carbonates, nitrates and borates” and there in the department of “anhydrous carbonates”. Here it is together with dolomite, kutnohorite and minrecordite in the "dolomite group (Trigonal:) " with the system no. 01/14/01 to be found in the subsection of " Anhydrous carbonates with the formula A + B 2+ (CO 3 ) 2 ".
Education and Locations
Anchorite forms in medium to low-grade, hydrothermal dykes , but also through metamorphosis or sedimentation in various iron stones and carbonatites , where it is mostly found in paragenesis with siderite and dolomite .
So far (as of 2011), Ankerite has been found at around 2300 sites worldwide. The "Tui Mine" near Te Aroha in New Zealand and the " Gilman Mine" in Eagle County in the USA, from which crystals up to 5 cm in size could be recovered, as well as Kladno and other places in the Czech Republic, are worth mentioning due to their special mineral finds . where crystals about one centimeter in size were found in concretions .
In addition to its type locality Erzberg in Styria, the mineral was also found in Austria near Badersdorf , Stadtschlaining and Redlschlag in Burgenland; in many areas of Carinthia ; near Kirchberg am Wechsel and Semmering in Lower Austria; in several regions of Salzburg and Styria ; found in north and east Tyrol as well as in the Montafon valley in Vorarlberg.
In Germany, Ankerit was among others in the Black Forest (Baden-Württemberg), in the Fichtelgebirge , Bavarian Forest and Upper Palatinate Forest (Bavaria); Odenwald , Spessart and Taunus (Hessen); in the Harz (Lower Saxony); in the Bergisches Land , Sauerland , Siegerland and the Eifel (North Rhine-Westphalia); in the Hunsrück and Westerwald (Rhineland-Palatinate); in the Ore Mountains (Saxony) as well as near Gera , in the Thuringian Forest and near Saalfeld / Saale (Thuringia).
In Switzerland, Ankerit was mainly found in the cantons of Graubünden , Ticino and Valais .
Other locations include Afghanistan , Egypt , Algeria , Angola , Argentina , Armenia , Australia , Belgium , Bolivia , Bosnia and Herzegovina , Brazil , Bulgaria , Chile , China , Ecuador , Fiji , Finland , France , Ghana , Greece , Greenland , Guatemala , Guyana , India , Indonesia , Iran , Ireland , Italy , Japan , Canada , Jersey Channel Island , Kazakhstan , Kyrgyzstan , Luxembourg , Colombia , Korea , Kosovo , Croatia , Madagascar , Malawi , Mali , Malta , Morocco , Mauritania , Mexico , Mongolia , Namibia , Netherlands , New Zealand , Norway , Oman , Pakistan , Peru , Philippines , Poland , Portugal , Romania , Russia , Sweden , Zimbabwe , Slovakia , Slovenia , Spain , South Africa , Tajikistan , Tanzania , Taiwan , Tunisia , Turkey , Ukraine , Hungary , Uzbekistan , Venezuela in the United Kingdom (Great Britain), the United States of America (USA) and Vietnam .
Crystal structure
Anchorite crystallizes trigonal in the space group R 3 (space group no. 148) with the lattice parameters a = 4.84 Å and c = 16.19 Å as well as 3 formula units per unit cell .
use
Anchorite is used as an additive in iron smelting.
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. 287 .
- ↑ Webmineral - Ankerite (English)
- ↑ a b Handbook of Mineralogy - Ankerite (English, PDF 64.5 kB)
- ↑ a b Ankerite at mindat.org (engl.)
- ↑ Mindat - Localities of Ankerite
See also
literature
- Petr Korbel, Milan Novák: Encyclopedia of Minerals . Nebel Verlag GmbH, Eggolsheim 2002, ISBN 3-89555-076-0 , p. 117 .
- Martin Okrusch, Siegfried Matthes: Mineralogy: An introduction to special mineralogy, petrology and deposit science . 7th edition. Springer Verlag, Berlin, Heidelberg, New York 2005, ISBN 3-540-23812-3 , pp. 67 .
Web links
- Mineral Atlas: Ankerite (Wiki)