Corderoite
| Corderoite | ||
|---|---|---|
Specific gravity 6.845 calc. | | |
| Optical properties | Isotropic | |
| Refractive index | n > 2.5 | |
| References | [2][3][4] | |
Corderoite is an extremely rare
isometric
crystal system. It is soft, 1.5 to 2 on the Mohs scale, and varies in color from light gray to black and rarely pink or yellow.
It was first described in 1974 for occurrences in the McDermitt Mercury mine in Humboldt County, Nevada. The name is from the old name of the mine, the Old Cordero Mine.[5]
Structure
The structure of Hg3S2Cl2 was determined in the 1960s before it was found in nature.[6] It has crankshaft chains that are crosswise linked by additional Hg²+.[citation needed] The crystals are
Å, the S-Hg-S angle being 165.1°. Each sulfide ion has three mercury ions near it, with the Hg-S-Hg angles being 94.1°. The nearest neighbors of a chloride ion are six mercury ions, at two somewhat different distances. A diagram can be seen on line, with blue balls representing mercury, green chlorine, and yellow sulfur.[7]
Various sulfide halides of
Hg share the feature of being face-sharing [HgS2X4]−6 polyhedral, with X=Cl in the case of corderoite.
Geologic occurrence
The main occurrence of corderoite in the
playa sediments within a thick zone, around 5–7 m (16–23 ft), sub parallel to bedding. Lake sediments including altered rhyolitic tuff and ash were deposited on the Tertiary rhyolitic volcanic rocks. Corderoite occurs as isolated grains or with cinnabar as replacements. Corderoite occurs as a low temperature supergene mineral.[6]
References
- S2CID 235729616.
- ^ http://rruff.geo.arizona.edu/doclib/hom/corderoite.pdf Handbook of Mineralogy
- ^ http://www.mindat.org/min-1127.html Mindat with location data
- ^ http://www.webmineral.com/data/Corderoite.shtml Webmineral data
- ^ http://www.mindat.org/loc-4206.html Mindat McDermii Mine page
- ^ a b Berendsen P., Foord E. E., and Storey L. O. (1974) "Corderoite, first natural occurrence of Hg3S2Cl2, from the Cordero mercury deposit, Humboldt County, Nevada". American Mineralogist, 59, 652–655 http://www.minsocam.org/ammin/AM59/AM59_652.pdf
- ^ "Corderoite". American Mineralogist Crystal Structure Database. Click on "View JMOL 3-D Structure".
- Grenchischev O. K. and Vasil'ev V. I. (1978) "First find of Corderoite (Hg3S2Cl2) in mercury ores of USSR". Doklady. 246/1-6, 145.
- Keller P., Lissner F., and Schleid T. (2005) "Single-crystal structure determination of Perroudite, Hg5Ag4S5 (I,Br)2Cl2, from Tsumeb (Namiba), and its structural relationships to other sulfide halides of mercury and cinnabar." Stuttgart 181/1, 1–9.
- Lavrent'ev Y. G. and Vasil'ev V. I. (1986) "New finds and data on the composition of corderoite (Hg3S2Cl2)". Soviet Geology and Geophysics, 27/12, 117–121.
- Modreski P. J. (1998) "Eugene Edward Foord, 1946–1998". The Canadian Mineralogist, 36/2, 251–254.