Potarit
| Potarit | |
|---|---|
 |
|
| General and classification | |
| chemical formula | PdHg |
|
Mineral class (and possibly department) |
Elements - metals and intermetallic compounds |
|
System no. to Strunz and to Dana |
1.AD.25 ( 8th edition : I / A.02) 02/01/04/04 |
| Crystallographic Data | |
| Crystal system | tetragonal |
| Crystal class ; symbol | ditetragonal-dipyramidal; 4 / m 2 / m 2 / m |
| Space group | P 4 / mmm (No. 123) |
| Lattice parameters | a = 3.03 Å ; c = 3.70 Å |
| Formula units | Z = 1 |
| Physical Properties | |
| Mohs hardness | 3.5 |
| Density (g / cm 3 ) | 14.88 |
| Cleavage | is missing |
| colour | cream-colored to whitish-cream-colored |
| Line color | silver-white |
| transparency | opaque |
| shine | Metallic luster |
Potarite is a very rarely occurring mineral from the mineral class of metals , alloys and intermetallic alloys . It crystallizes in the tetragonal crystal system with the chemical formula PdHg and forms cream-colored to silver-white massive grains and nuggets of up to 1 cm in size.
Etymology and history
Potarit was first found and described by JB Harrison in 1924–1925. Further investigations and comparisons with known artificial palladium - mercury compounds - so-called amalgams - were carried out by Spencer in 1928, Cissarz in 1930 and MA Peacock in 1945. Spencer's idea that potarite could be the same as allopalladium (now stibiopalladinite ) has not been confirmed.
The mineral is named after the Potaro River in Guyana , where the type locality is near the Kaieteur Falls .
classification
In the Strunz system , Potarit is counted among the metals and intermetallic compounds, a subgroup of the elements. After the 8th edition, it forms a group together with Belendorffite , lead amalgam , eugenite , gold amalgam , kolymite , luanheit , moschellandsbergite , paraschachnerite , mercury , schachnerite and weishanite . In the 9th edition , it forms a separate subgroup of the mercury amalgam family.
In the Dana systematics , it forms with tetraferroplatinum, tulameenite and ferronickelplatinum, a subgroup of the metallic elements with platinum metals and alloys.
Education and Locations
Potarite is found in ultramafitic rocks such as dunite and chromidite, as well as areas where gold and diamonds are found. It is associated with platinum , palladium, gold, pentlandite , chalcopyrite , pyrrhotite and millerite . Potarit often also contains copper .
A total of only 17 locations (as of March 2010) of the Potarit are known. In addition to the type locality, these include Pilbara in Australia , Curionópolis and Serro in Brazil , Chaudière-Appalaches in Canada , the Tottori prefecture in Japan , Bleida in Morocco , the island of Ouen , which belongs to New Caledonia , Siberia and the Urals in Russia , the Bushveld complex in South Africa , the Scottish island of Rum and Goodnews Bay , the Stillwater Complex and Goodsprings in the United States .
Crystal structure
Potarit crystallizes in the tetragonal crystal system with the space group P 4 / mmm (space group no. 123) , the lattice parameters a = 3.03 Å and c = 3.70 Å and one formula unit per unit cell .
See also
Individual evidence
- ^ Potarit in: Anthony et al .: Handbook of Mineralogy , 1990, 1, 101 ( pdf )
- ↑ Allopalladium at Mindat.org
- ^ New Dana Classification of Native Elements
- ↑ mindat.org Potarite (English)
literature
- Potarit in: Anthony et al .: Handbook of Mineralogy. 1990, 1, 101 ( pdf )
- K. Terada, FW Cagle, Jr .: The crystal structure of potarite (PdHg) with some comments on allopalladium. In: American Mineralogist. 1960, 45, 1093-1097 ( pdf ).
Web links
- Mineral Atlas: Potarit (Wiki)
- mindat.org Potarite (English)