Cryptochalcite
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About Cryptochalcite
Formula:
K2Cu5O(SO4)5
Colour:
Light green to green
Lustre:
Vitreous
Specific Gravity:
3.41 (Calculated)
Crystal System:
Triclinic
Name:
Named from Greek κρυπτóς, concealed, and χαλκóς, copper.
New structure type. The K (or K2-) analogue of cesiodymite.
Visually indistinguishable from cesiodymite.
Visually indistinguishable from cesiodymite.
Classification of Cryptochalcite
Physical Properties of Cryptochalcite
Vitreous
Transparency:
Transparent
Colour:
Light green to green
Tenacity:
Brittle
Density:
3.41 g/cm3 (Calculated)
Optical Data of Cryptochalcite
Type:
Biaxial (-)
RI values:
nα = 1.610(3) nβ = 1.632(4) nγ = 1.643(4)
2V:
Measured: 65° (5)
Max Birefringence:
δ = 0.033

Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
Moderate
Chemical Properties of Cryptochalcite
Formula:
K2Cu5O(SO4)5
Elements listed:
Crystallography of Cryptochalcite
Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
Cell Parameters:
a = 10.0045(3) Å, b = 12.6663(4) Å, c = 14.4397(5) Å
α = 102.194(3)°, β = 102.194(3)°, γ = 90.008(3)°
α = 102.194(3)°, β = 102.194(3)°, γ = 90.008(3)°
Ratio:
a:b:c = 0.79 : 1 : 1.14
Unit Cell V:
1751.7 ų
Z:
4
Morphology:
Coarse tabular or prismatic crystals; grains up to 0.3 mm.
X-Ray Powder Diffraction
Powder Diffraction Data:
d-spacing | Intensity |
---|---|
g = 90.008 | (3)º13.9 |
6.95 | (100) |
6.22 | (45) |
3.93 | (65) |
3.76 | (30) |
3.39 | (30) |
3.19 | (35) |
2.500 | (40) |
Comments:
From Type Description.
Occurrences of Cryptochalcite
Paragenetic Mode(s):
• Fumarolic
Type Occurrence of Cryptochalcite
General Appearance of Type Material:
Coarse tabular or prismatic crystals or grains up to 0.3 mm
Place of Conservation of Type Material:
Type material is deposited in the collections of the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow, Russia, registration number 4675/1
Geological Setting of Type Material:
Fumarole
Associated Minerals at Type Locality:
Reference:
Pekov, I.V., Zubkova, N.V., Agakhanov, A.A., Pushcharovsky, D.Yu., Yapaskurt, V.O., Belakovskiy, D.I., Vigasina, M.F., Sidorov, E.G., Britvin, S.N. (2018): Cryptochalcite, K2Cu5O(SO4)5, and cesiodymite, CsKCu5O(SO4)5, two new isotypic minerals and the K-Cs isomorphism in this solid-solution series. European Journal of Mineralogy, 30: 593-607
Synonyms of Cryptochalcite
Other Information
Health Risks:
No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.
References for Cryptochalcite
Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Pekov, I.V., Zubkova, N.V., Agakhanov, A.A., Yapaskurt, V.O., Belakovskiy, D.I., Vigasina, M.F., Sidorov, E.G. and Pushcharovsky, D.Y. (2015) Cryptochalcite, IMA 2014-106. CNMNC Newsletter No. 25, June 2015, page 530; Mineralogical Magazine, 79, 529-535.
Pekov, I.V., Zubkova, N.V., Agakhanov, A.A., Pushcharovsky, D.Yu., Yapaskurt, V.O., Belakovskiy, D.I., Vigasina, M.F., Sidorov, E.G., Britvin, S.N. (2018): Cryptochalcite, K2Cu5O(SO4)5, and cesiodymite, CsKCu5O(SO4)5, two new isotypic minerals and the K-Cs isomorphism in this solid-solution series. European Journal of Mineralogy, 30: 593-607.
Internet Links for Cryptochalcite
mindat.org URL:
https://www.mindat.org/min-46612.html
Please feel free to link to this page.
Please feel free to link to this page.
External Links:
Mineral Dealers:
Localities for Cryptochalcite
Locality List




All localities listed without proper references should be considered as questionable.
Russia (TL) | |
| Pekov, I.V., Zubkova, N.V., Agakhanov, A.A., Yapaskurt, V.O., Belakovskiy, D.I., Vigasina, M.F., Sidorov, E.G. and Pushcharovsky, D.Y. (2015) Cryptochalcite, IMA 2014-106. CNMNC Newsletter No. 25, June 2015, page 530; Mineralogical Magazine, 79, 529-535. ;Pekov, I.V., Zubkova, N.V., Agakhanov, A.A., Pushcharovsky, D.Yu., Yapaskurt, V.O., Belakovskiy, D.I., Vigasina, M.F., Sidorov, E.G., Britvin, S.N. (2018): Cryptochalcite, K2Cu5O(SO4)5, and cesiodymite, CsKCu5O(SO4)5, two new isotypic minerals and the K-Cs isomorphism in this solid-solution series. European Journal of Mineralogy, 30, 593-607 |
Arsenatnaya fumarole, Second scoria cone, Northern Breakthrough, Great Fissure eruption, Tolbachik volcano, Kamchatka Krai, Russia