Ankerite

Ankerite ( dolomite ) is a commonly occurring mineral from the mineral class of anhydrous carbonates without foreign anions. It crystallizes in the trigonal crystal system with the chemical composition CaFe [ CO3 ] 2 and usually develops rhombohedral crystals, but also granular aggregates in white, gray-brown or brownish-yellow color with a white stroke color.

Ankerite forms a mixed batch with dolomite ( CaMg [ CO3 ] 2 ) and Kutnohorit ( CaMn [ CO3 ] 2).

Etymology and history

Was first discovered in ankerite 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In the now outdated but still in use 8th edition of the mineral classification by Strunz the ankerite belonged to the mineral class of " carbonates, nitrates and borates " and then to the Department of " water clear carbonates without foreign anions ", where he along with Benstonit, dolomite, Ewaldit, huntite, Kutnohorit, Minrecordit and Norsethit the " dolomite group " was formed.

The 9th edition used since 2001 and valid by the International Mineralogical Association (IMA ) of the Strunz'schen Mineral classification assigns the ankerite 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 nature of the cations involved, so that the mineral is found according to its composition in the subsection " alkaline-earth (and other M2 ) carbonates " where there is only together with dolomite, Kutnohorit and Minrecordit the " dolomite group "with the system no. 5.AB.10 forms.

The classification of minerals according to Dana assigns the ankerite as the outdated 8th edition of the Strunz'schen systematics in the common class of " carbonates, nitrates and borates " and there in the department of " water clear carbonates ". Here he is with dolomite, Kutnohorit and Minrecordit in the " dolomite group ( Trigonal: ) " with the system no. 14:01:01 within the sub-division of " water clear 2 carbonates having the formula A B2 ( CO3) " to find.

Education and Locations

Ankerite formed in medium-to low-grade, hydrothermal veins, but also through metamorphosis or sedimentation in various iron rocks and carbonatites, where it is usually found in paragenesis with siderite and dolomite.

Could Worldwide ankerite so far (as of 2011) are detected in about 2,300 localities. Worth mentioning among other things the " Tui Mine" at Te Aroha in New Zealand and the " Gilman Mine" in Eagle County in the United States, from which up to 5 cm large crystals were recovered and Kladno and other places in the Czech Republic because of their special mineral finds, where large crystals were found in concretions about an inch.

Apart from its type locality Erzberg in Styria in Austria nor in the mineral Badersdorf, Stadtschlaining and Redlschlag in Burgenland; in many parts of Carinthia; in Kirchberg am Wechsel and Semmering in Lower Austria; in several regions of Salzburg and Styria; in North and East Tyrol and in the Montafon found in Vorarlberg.

In Germany, ankerite, among others, in the Black Forest (Baden- Württemberg), in the Fichtelgebirge, the Bavarian Forest, Upper Palatinate Forest ( Bavaria ); Odenwald, Spessart and Taunus ( Hesse ); in the Harz (Lower Saxony ); in Bergisch Land, Sauerland, winner country and in the Eifel (Nordrhein-Westfalen ); in the Hunsrück and Westerwald ( Rhineland -Palatinate ); in the Erzgebirge (Saxony ) and in Gera, in the Thuringian forest and in Saalfeld / Saale ( Thuringia).

In Switzerland, ankerite found mainly in the cantons of Graubünden, Ticino and Valais.

Other localities include Afghanistan, 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, the channel Island of jersey, Kazakhstan, Kyrgyzstan, Luxembourg, Colombia, Korea, Croatia, Kosovo, 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, the United Kingdom ( UK), the United States of America ( USA) and Vietnam.

Crystal structure

Ankerite crystallized trigonal space group R3 ( Raumgruppen-Nr. 148) with the lattice parameters a = 4.84 Å and c = 16.19 Å and 3 formula units per unit cell.

Use

Ankerite is used as an additive in iron smelting.

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