Chrysothallite

Chrysothallite
General
Category Halide mineral
Formula
(repeating unit)
K6Cu6Tl3+Cl17(OH)4•H2O
Crystal system Tetragonal, I4/mmm
Space group Tetragonal - Ditetragonal Dipyramidal (4/mmm)
Unit cell a=11.37, b=26.21 (approximated)
Identification
Color Golden-yellow to light yellow
Crystal habit tabular
Cleavage None
Fracture Uneven
Tenacity Brittle
Luster Vitreous
Streak White
Diaphaneity Transparent
Density 2.95 (measured)
Optical properties Uniaxial (+)
Refractive index ω=1.72, ε=1.73 (approximated)
References [1][2]

Chrysothallite is a rare thallium-bearing chloride mineral with the formula K6Cu6Tl3+Cl17(OH)4•H2O.[1][2] Chrysothallite is unique in being only the second mineral with essential trivalent thallium,[1] a feature shared with natural thallium(III) oxide, avicennite.[3] Another examples of natural thallium chlorides are steropesite, Tl3BiCl6, and lafossaite, TlCl.[4][5] Chrysothallite is one of numerous fumarolic minerals discovered among fumarolic sites of the Tolbachik volcano, Kamchatka, Russia[6] The mineral is named in allusion to its colour and thallium content.[1]

Notes on chemistry

Chrysothallite contains a relative high amount of zinc admixture. Zinc is substituting for copper.[1]

Association and origin

Chrysothallite may be associated with many other minerals:[1]

Crystal structure

The crystal structure of chrysothallite is unique. Its building elements are:[1]

Origin

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 150 °C (302 °F).

References

  1. 1 2 3 4 5 6 7 Pekov, I.V., Zubkova, N.v., Belakovskiy, D.I., Yapaskurt, V.O., Vigasina, M.F., Lykova, I.S., Sidorov, E.G., and Pushcharovsky, D.Yu., 2015. Chrysothallite K6Cu6Tl3+Cl17(OH)4.H2O, a new mineral species from the Tolbachik volcano, Kamchatka, Russia. Mineralogical Magazine 79(2), 365-376
  2. 1 2 "Chrysothallite: Chrysothallite mineral information and data". Mindat.org. Retrieved 2016-03-11.
  3. "Avicennite: Avicennite mineral information and data". Mindat.org. Retrieved 2016-03-11.
  4. "Steropesite: Steropesite mineral information and data". Mindat.org. Retrieved 2016-03-11.
  5. "Lafossaite: Lafossaite mineral information and data". Mindat.org. Retrieved 2016-03-11.
  6. "Tolbachik volcano, Kamchatka Oblast', Far-Eastern Region, Russia - Mindat.org". Mindat.org. Retrieved 2016-03-11.


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