Dachiardite-K is a rare zeolite-group mineral with the formula K4(Si20Al4O48)•13H2O.[5][3] It is the potassium-analogue of dachiardite-Ca and dachiardite-Na, as suggested by the suffix "-K".[6][2][7] Dachiardite honors Italian geologist and mineralogist Antonio D'Achiardi. In 1906, his son and mineralogist Giovanni D'Achiardi described and named the mineral dachiardite after he discovered it in a granitic pegmatite.[8][9]
| Dachiardite-K | |
|---|---|
| General | |
| Category | Tectosilicate minerals |
| Group | Zeolite group |
| Formula | 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][4] |
Occurrence and association
editDachiardite-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.
- 1 2 "Dachiardite-K: Dachiardite-K mineral information and data". Mindat.org. Retrieved 2016-03-04.
- 1 2 3 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: 17–18. Retrieved 2 January 2026.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ↑ Chukanov, N.V., Encheva, S., Petrov, P., Chukanov, N., and Pekov, I. (2016). "Dachiardite-K, (K2Ca)(Al4Si20O48) · 13H2O, a new zeolite from Eastern Rhodopes, Bulgaria". Geol. Ore Deposits. 58: 666–673. doi:10.1134/S1075701516080079.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ↑ 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 (27): 1224.
{{cite journal}}: CS1 maint: multiple names: authors list (link); U. H ÅLENIUS 1 (Chairman, CNMNC), F. HATERT (Vice-Chairman, CNMNC), M. PASERO (Vice-Chairman, CNMNC) AND S. J. M ILLS (Secretary, CNMNC) (October 2015). "IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) New minerals and nomenclature modifications approved in 2015". Mineralogical Magazine. 79 (5): 1224. doi:10.1180/minmag.2015.079.5.16.{{cite journal}}: CS1 maint: multiple names: authors list (link) CS1 maint: numeric names: authors list (link) - ↑ "dachiardite". Merriam-Webster Dictionary. Retrieved 30 May 2024.
- ↑ "Dachiardite-K" (PDF). Handbook of Mineralogy. Retrieved 2 January 2026.
- ↑ Sartori, Franco (1985). "D'ACHIARDI, Giovanni". Dizionario Biografico degli Italiani (in Italian). Vol. 31. Retrieved 27 May 2024.
- ↑ Berman, Harry (1925). "Notes on dachiardite". American Mineralogist. 10 (11): 421–428.
External links
edit- "Dachiardite-K" (in Bulgarian). Earth and Man National Museum, Sofia, Bulgaria. Retrieved 23 December 2025.
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