Mackinawit
| Mackinawit | |
|---|---|
 |
|
| General and classification | |
| chemical formula | (Fe, Ni) 9 S 8 |
|
Mineral class (and possibly department) |
Sulfides and sulfosalts |
|
System no. to Strunz and to Dana |
2.CC.25 ( 8th edition : II / B.17) 07/02/02/01 |
| Crystallographic Data | |
| Crystal system | tetragonal |
| Crystal class ; symbol | ditetragonal-dipyramidal 4 mm |
| Space group | P 4 / nmm |
| Lattice parameters | a = 3.67 Å ; c = 5.03 Å |
| Formula units | Z = 2 |
| Physical Properties | |
| Mohs hardness | 2.5 |
| Density (g / cm 3 ) | 4.30 |
| Cleavage | completely along {001} |
| colour | bronze-colored, white-gray |
| Line color | black |
| transparency | opaque |
| shine | Metallic luster |
| Crystal optics | |
| Pleochroism | strong |
Mackinawit is a mineral from the mineral class of " sulphides and sulphosalts ", which can sometimes be abundant in various locations, but is generally not very common. It crystallizes in the tetragonal crystal system with the chemical composition (Fe, Ni) 9 S 8 and sometimes develops thin, tabular crystals up to 1 mm in size of bronze or white-gray color. It is much more common, however, to find it in the form of tiny, irregular tinsel or inclusions in chalcopyrite or pentlandite .
Etymology and history
Mackinawit was first found in 1963 by HT Evans, Charles Milton, and others at the Mackinaw Mine in Snohomish County , Washington state . The mineral was named after its type locality .
Mackinawit used to be confused with the very similar looking Valleriit . The similarity and distribution are so similar that the two minerals were mistaken for one mineral. Valleriite, however, has a different chemical composition and is also softer than mackinawit.
classification
In the meanwhile outdated, but still in use 8th edition of the mineral classification according to Strunz , the Mackinawit belonged to the mineral class of "sulfides and sulfosalts" and there to the department of "sulfides with the molar ratio of metal: sulfur, selenium, tellurium> 1: 1", where he formed an independent group together with Godlevskit and Kharaelakhit .
The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), also assigns the mackinawit to the class of "sulfides and sulfosalts" and there in the department of "metal sulfides, M: S = 1: 1 (and similar) ”. This division is, however, further subdivided according to the predominant metals in the compound, so that the mineral, depending on its composition, can be found in the sub-division "with nickel (Ni), iron (Fe), cobalt (Co) etc.", where it can be found as the only member is the unnamed group 2.CC.25 .
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the Mackinawit to the class of "sulfides and sulfosalts" and there in the department of "sulfide minerals". Here he is to be found as the only member of the unnamed group 02.07.02 within the subdivision of " Sulphides - including selenides and tellurides - with the composition A m B n X p , with (m + n): p = 9: 8 " .
Education and Locations
Mackinawit forms hydrothermally in mineral deposits and during serpentinization of peridotite . Mackinawit can also form in water sludge under reducing conditions, and sulfate-reducing bacteria are also suspected to be involved. It is also rarely found in some meteorites, the carbonaceous chondrites .
Overall, Mackinawit has so far (as of 2011) been detected at around 230 sites. In Germany the mineral occurred at Hagendorf ( Waidhaus ) in Bavaria and at Rammelsberg in Lower Saxony.
In Austria Mackinawit was found on the Hüttenberger Erzberg and on the Lamprechtsberg in Carinthia; in the Leckbachgraben in the Habach Valley , at the Murwinkel and in the Schwarzleograben in Salzburg; near Voitsberg in Styria and in the Tyrolean Inntal .
In Switzerland, the mineral was found near Palagnedra in the canton of Ticino and in the Binntal and Eringertal in the canton of Valais.
Other locations are in Egypt , Algeria , Argentina , Australia , Brazil , Bulgaria , China , Finland , France , Greenland , India , Indonesia , Italy , Canada , Kazakhstan , Japan , Morocco , Mauritania , Nigeria , Norway , Oman , Pakistan , Peru , Poland , Portugal , Romania , Russia , Sweden , Senegal , Zimbabwe , Spain , South Africa , Turkey , the United Kingdom (Great Britain) and the United States, and Cyprus .
Mackinawit could also be detected in rock samples from the Red Sea (Atlantis II Deep) and outside the earth on the moon .
Crystal structure
Mackinawit crystallizes in the tetragonal crystal system in the space group P 4 / nmm , the lattice parameters a = 3.67 Å and c = 5.03 Å as well as two formula units per unit cell .
See also
Individual evidence
- ↑ a b c Webmineral - Mackinawite (Engl.)
- ↑ Stefan Weiß: The large Lapis mineral directory . 4th edition. Christian Weise Verlag, Munich 2002, ISBN 3-921656-17-6
- ^ A b Paul Ramdohr , Hugo Strunz : Textbook of Mineralogy . 16th edition. Ferdinand Enke Verlag 1978, ISBN 3-432-82986-8 (p. 449)
- ↑ Mindat - Localities for Mackinawite
literature
- Mackniawit in: Anthony et al .: Handbook of Mineralogy , 1990, 1, 101 ( pdf )
Web links
- Mineral Atlas: Mackinawit (Wiki)
- mindat.org - Mackinawite (Eng.)