Metacinnabarite
| Metacinnabarite | |
|---|---|
 |
|
| General and classification | |
| chemical formula | HgS |
|
Mineral class (and possibly department) |
Sulfides and sulfosalts |
|
System no. to Strunz and to Dana |
2.CB.05a ( 8th edition : II / C.01) 08/02/02/03 |
| Crystallographic Data | |
| Crystal system | cubic |
| Crystal class ; symbol | cubic-hexakistrahedral; 4 3 m |
| Space group | F 4 3 m (No. 216) |
| Lattice parameters | a = 5.852 Å |
| Formula units | Z = 2 |
| Twinning | often along {111} |
| Physical Properties | |
| Mohs hardness | 3 |
| Density (g / cm 3 ) | 7.65 |
| Cleavage | is missing |
| Break ; Tenacity | subconchoidal |
| colour | grey black |
| Line color | black |
| transparency | opaque |
| shine | metallic |
Metacinnabarite is a rarely occurring mineral from the mineral class of sulfides and sulfosalts . It crystallizes in the cubic crystal system with the chemical composition HgS and forms mostly massive aggregates, rarely also tetrahedral , up to one millimeter large crystals of gray-black color.
Etymology and history
Metacinnabarite was first found in 1872 by Gideon Moore in the type locality , the Redington Mine in Knoxville , California. It is so named because of its similarity to the mineral cinnabarite .
classification
In the Strunz system , metacinnabarite is counted among the metal sulfides with a ratio of metal to sulfur, selenium or tellurium of 1: 1. After the 8th edition , together with Coloradoite , Hawleyite , Rudashevskyite , Polhemusite , Sphalerite , Stilleit and Tiemannite form the Sphalerite group. In the 9th edition it forms with these minerals and sakuraiite a subgroup of the sulfides with zinc , iron , copper or silver .
In the Dana systematics , it forms with Coloradoite, Hawleyite, Rudashevskyite, Sphalerite, Stilleit and Tiemannite the sphalerite subgroup of sulphides, selenides and tellurides with the composition A m B n X p , with (m + n): p = 1: 1.
Modifications and varieties
Metacinnabar is one of three modifications of mercury (II) sulfide , along with the trigonal cinnabar and the hexagonal hypercinnabar . It is metastable and can transform into cinnabarite. Metacinnabarite is the more stable modification only above 344 ° C.
Five varieties of metacinnabarites are known. These are the zinc-containing Guadalcazarit , the cadmium-containing Saukovit and three selenium-containing Metacinnabarit varieties, including Kittlit and Onofrit .
Education and Locations
Metacinnabar forms at low temperatures in near-surface mercury deposits. It is associated with cinnabarite, mercury, wurtzite , stibnite , marcasite , realgar , calcite , barite and hydrocarbons.
Metacinnabarite is found, occasionally as the main ore, in many mercury deposits. In addition to the type locality Read Island in Canada , San Onofre in Colombia , Guadalcázar in Mexico , Idrija in Slovenia , Levigliani in Italy , Baia Sprie in Romania , Almadén in Spain , the Altai and other localities in Russia , as well as the US States of California, Texas , Utah, and Washington .
Crystal structure
Metacinnabarite crystallizes in the cubic crystal system in the space group with the lattice parameter a = 5.872 Å and two formula units per unit cell . The structure corresponds to a sphalerite structure.
Precautions
The mercury contained in the mineral is poisonous. Appropriate precautionary measures must therefore be taken when handling so that it does not get into the body.
See also
Individual evidence
- ^ RWG Wyckoff, Crystal Structures , 2nd edition, Interscience publishers, New York, USA.
- ^ A b Frank W. Dickson, George Tunell: The stability relations of cinnabar and metacinnabar. In: American Mineralogist. 1959, 44, pp. 471-487 ( PDF ).
- ^ New Dana Classification of Sulfide Minerals
- ↑ Metacinnabarite at mindat.org (Eng.)
literature
- Metacinnabarit in: Anthony et al .: Handbook of Mineralogy , 1990, 1, 101 ( pdf ).
