| Chrysothallite | |
| Category: | Halide mineral |
| Formula: | K6Cu6Tl3+Cl17(OH)4•H2O |
| Imasymbol: | Cry[1] |
| System: | Tetragonal |
| Class: | Ditetragonal dipyramidal (4/mmm) H-M symbol: (4/m 2/m 2/m) |
| Symmetry: | I4/mmm |
| Unit Cell: | a = 11.37 Å, b = 26.21 Å (approximated); Z = 4 |
| Color: | Golden-yellow to light yellow |
| Habit: | tabular |
| Cleavage: | None |
| Fracture: | Uneven |
| Tenacity: | Brittle |
| Luster: | Vitreous |
| Streak: | White |
| Diaphaneity: | Transparent |
| Density: | 2.95 (measured) |
| Opticalprop: | Uniaxial (+) |
| Refractive: | ω=1.72, ε=1.73 (approximated) |
| References: | [2] [3] |
Chrysothallite is a rare thallium-bearing chloride mineral with the formula K6Cu6Tl3+Cl17(OH)4•H2O.[4] Chrysothallite is unique in being only the second mineral with essential trivalent thallium, a feature shared with natural thallium(III) oxide, avicennite.[5] Another examples of natural thallium chlorides are steropesite, Tl3BiCl6, and lafossaite, TlCl.[6] [7] Chrysothallite is one of numerous fumarolic minerals discovered among fumarolic sites of the Tolbachik volcano, Kamchatka, Russia[8] The mineral is named in allusion to its colour and thallium content.
Chrysothallite contains a relative high amount of zinc admixture. Zinc is substituting for copper.
Chrysothallite may be associated with many other minerals:
The crystal structure of chrysothallite is unique. Its building elements are:
Chrysothallite is supposed to be a product of interaction of relatively high-temperature fumarolic minerals with fumarolic gas and atmospheric water, that takes place in temperatures up to .