Otavite
- Cadmiumspat
Otavit or Cadmiumspat is a rarely occurring mineral from the mineral class of " carbonates ( and relatives ) ." It crystallizes in the trigonal crystal system with the composition Cd [ CO3 ] is so chemically seen a cadmium carbonate, which is found predominantly in the form of crusty coatings, but rarely developed rhombohedral crystals to about two millimeters in size.
Pure Otavitkristalle are colorless and transparent. Through multiple refraction due to lattice defects or polycrystalline training Otavit can also appear white and accept by foreign admixtures a yellowish -brown to reddish-brown tint. Visible crystal surfaces have a strong glass to adamantine, microcrystalline, crusty on the other hand forms a rather pearly.
Special Features
Otavit dissolves like calcite very easily in hydrochloric acid and froths on underserved roaring noise. Hydrogen sulfide produced a yellow precipitate cadmium and also before the blowpipe on charcoal shows a characteristic cadmium fitting.
Under UV light, show some Otavite red fluorescence, similar to that of neon-colored highlighters.
Etymology and history
Otavit was first discovered in the Tsumeb mine in Namibia and described in 1906 by Otto Schneider, after his discovery area, the Otavibergen, named the mineral.
Classification
In the now outdated but still in use 8th edition of the mineral classification by Strunz the Otavit " water outdoors carbonates without foreign anions " belonged to the common mineral class of " carbonates, nitrates and borates " and then to the Department of where he together with calcite, Gaspéit, magnesite, rhodochrosite, siderite, smithsonite, and vaterite Sphärocobaltit the " Calcitgruppe " was formed.
The 9th edition used since 2001 and valid by the International Mineralogical Association (IMA ) of the Strunz'schen Mineral classification assigns the Otavit 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 it together with calcite, Gaspéit, magnesite, rhodochrosite, siderite, Smithsonite and Sphärocobaltit the " Calcitgruppe " with the system no. 5.AB.05 forms.
The classification of minerals according to Dana assigns the Otavit 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 calcite, magnesite, siderite, rhodochrosite, Sphärocobaltit, Smithsonite and Gaspéit in the " Calcitgruppe ( trigonal R - 3c)" with the system no. 14:01:01 within the sub-division of " water clear CO3 carbonates with a simple formula A " to find.
Education and Locations
Otavit forms as a rare secondary mineral in the oxidation zone of hydrothermal ore deposits. Accompanying minerals include azurite, calcite, cerussite, fluorite, hemimorphite Hydrozincite, malachite, Olivenit, pyromorphite, Rosasit and Smithsonite.
Overall Otavit has so far (as of 2011) are detected in approximately 20 localities, including, inter alia at Broken Hill in Australia; Duyun in China; Rohdenhaus ( Wülfrath ) in Germany; Lavrio (s) in Greece; the Burren in Ireland; Arbus and Ozieri in Italy; Hinokage in the Japanese prefecture of Miyazaki; Probistip in Macedonia; Verkhoyansk in Russia; Horni Rokytnice (Upper Rochlitz ) to Harrachov in the Czech Republic; Legyesbénye in Hungary; Greenhow (England), Bishopton (Scotland) and Wethel (Wales ) UK ( United Kingdom ); on the Huron River ( Michigan), at Sterling Hill (New Jersey) and Bingham (New Mexico) in the United States of America ( USA) and Mo Ba in Vietnam.
Crystal structure
Otavit trigonal crystallized in the space group R3c ( Raumgruppen-Nr. 167) with the lattice parameters a = 4.93 Å and c = 16.27 Å and 6 formula units per unit cell.