Paramelaconite
| Paramelaconite | |
|---|---|
 (comparative scale: 1 "(= 2.54 cm) with a notch at 1 cm) |
|
| General and classification | |
| chemical formula | Cu 2 1+ Cu 2 2+ O 3 |
|
Mineral class (and possibly department) |
Oxides and hydroxides |
|
System no. to Strunz and to Dana |
4.AA.15 ( 8th edition : IV / A.05) 04.06.04.01 |
| Crystallographic Data | |
| Crystal system | tetragonal |
| Crystal class ; symbol | 4 / mmm |
| Space group | I 4 1 / amd |
| Lattice parameters | a = 5.837 Å ; c = 9.932 Å |
| Formula units | Z = 4 |
| Physical Properties | |
| Mohs hardness | 4.5 |
| Density (g / cm 3 ) | 6.04 |
| Cleavage | is missing |
| Break ; Tenacity | shell-like |
| colour | black |
| Line color | black |
| transparency | opaque |
| shine | metallic, diamond luster |
Paramelaconite is a very rare mineral from the mineral class of oxides and hydroxides . It crystallizes in the tetragonal crystal system with the chemical composition Cu 2 1+ Cu 2 2+ O 3 and forms up to 7.5 cm large prismatic crystals of black color.
Etymology and history
Paramelaconite was first found in 1890 by AE Foote in the type locality , the Copper Queen Mine in Bisbee , Arizona . The mineral was examined in 1891 by August König , who described it as a tetragonal modification of copper (II) oxide and dimorphic to tenorite . This is where the name of the mineral comes from, as melaconite is now an outdated alternative name for tenorite. In 1941 Clifford Frondel was able to determine the exact composition of the paramelaconite by means of an X-ray structure analysis.
classification
In the Strunz system , tenorite is one of the oxides with a metal to oxygen ratio of 2: 1 and 1: 1. After the 8th edition it forms a group together with Crednerit , Delafossit , Mcconnellit and Tenorit. In the 9th edition it forms its own subgroup of oxides with a metal to oxygen ratio of 2: 1 (and 1.8: 1).
In the Dana system , it forms a separate subgroup of the simple, unclassified oxides.
Education and Locations
Paramelaconite very rarely forms as a secondary mineral under hydrothermal conditions in copper deposits. It is associated with cuprite , Tenorite, Connellit , malachite , goethite , in another locality with chrysocolla , Plancheite , Dioptas and Atacamit .
Only a small number of sites are known. In addition to the type locality in Bisbee, paramelaconite was also found in the Algomah mine in the US state of Michigan , Skouriotissa in Cyprus , Laurion in Greece and Budleigh Salterton in Devon ( England ),
Crystal structure
Paramelaconite crystallizes in the tetragonal crystal system in the space group I4 1 / amd with the lattice parameters a = 5.837 Å and c = 9.932 Å, as well as four formula units per unit cell .
See also
Individual evidence
- ↑ a b M. O'Keeffe, J.-O. Bovin: The crystal structure of paramelaconite, Cu 4 O 3 . In: American Mineralogist. 1978, 63, pp. 180-185 ( PDF ).
- ↑ George A. Koenig: On Paramelaconite, and the Associated Minerals. In: Proceedings of the Academy of Natural Sciences of Philadelphia. 1891, 43, pp. 284-291 ( abstract ).
- ↑ Clifford Frondel: Paramelaconite: a tetragonal oxide of copper. In: American Mineralogist. 1941, 11, pp. 657-672 ( PDF ).
- ^ New Dana Classification of Simple Oxides
- ↑ M. O'Keeffe, J.-O. Bovin: The crystal structure of paramelaconite, Cu 4 O 3 . In: American Mineralogist. 1978, 63, pp. 180-185 ( PDF ).
literature
- Paramelaconite in: Anthony et al .: Handbook of Mineralogy , 1990, 1, 101 ( pdf ).
