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Dachiardite-K 
Summary
Dachiardite-K is a rare zeolite-group mineral with the formula K4(Si20Al4O48)•13H2O.[4][3] It is the potassium-analogue of dachiardite-Ca and dachiardite-Na, as suggested by the suffix "-K".[2]
| Dachiardite-K | |
|---|---|
| General | |
| Category | Tectosilicate, Zeolite |
| Formula (repeating unit) | K4(Si20Al4O48)·13H2O |
| IMA symbol | Dac-K[1] |
| Crystal system | Monoclinic Unknown space group |
| Unit cell | a = 18.67, b = 7.51 c = 10.23 [Å], β = 107.79° (approximated) |
| Identification | |
| Color | Snow-white |
| Crystal habit | Needle-like crystals in spherical aggregates |
| Cleavage | (100), perfect |
| Fracture | Stepped across |
| Tenacity | Brittle |
| Mohs scale hardness | 4 |
| Density | 2.18 (measured), 2.17 (calculated; approximated) [g/cm3] |
| Optical properties | Biaxial (+) |
| Refractive index | nα=1.48, nβ=1.48, nγ=1.48 (approximated) |
| Pleochroism | No |
| 2V angle | 65o (measured) |
| Dispersion | Distinct |
| References | [2][3] |
Occurrence and association edit
Dachiardite-K was discovered in opal-chalcedony veins in Eastern Rhodopes, Bulgaria. It is associated with barite, calcite, clinoptilolite-Ca, clinoptilolite-K, celadonite, dachiardite-Ca, dachiardite-Na, ferrierite-K, ferrierite-Mg, ferrierite-Na, mordenite, and smectite.[3]
References edit
- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ a b "Dachiardite-K: Dachiardite-K mineral information and data". Mindat.org. Retrieved 2016-03-04.
- ^ a b c Encheva, S., Petrov, P., Chukanov, N., and Pekov, I., 2015. Dachiardite-K from the area of Austa village, Momchilgrad municipality, Eastern Rhodopes – a new mineral species of zeolite group. Bulgarian Geological Society, National Conference with international participation “GEOSCIENCES 2015”, 10-11 Dec 2015, Sofia, Bulgaria; pp. 17-18
- ^ Chukanov, N.V., Encheva, S., Petrov, P., Pekov, I.V., Belakovskiy, D.I., Britvin, S.N., and Aksenov, S.M., 2015. Dachiardite-K, IMA 2015-041. CNMNC Newsletter No. 27, October 2015, 1224; Mineralogical Magazine 79, 1229–1236