Dachiardite-Ca
Dachiardite-Ca is an IMA-recognized mineral species in the silicate class, with the chemical formula Ca₂(Si₂₀Al₄)O₄₈·13H₂O.
It crystallizes in the monoclinic crystal system (space group C2/m). It is a member of the Dachiardite structural group.
Key properties: Mohs hardness 4–4.5; specific gravity 2.17–2.21; Vitreous luster; optically biaxial.
IMA symbol Dac-Ca, IMA status: approved, named in 1906.
Of hydrothermal origin in basalt, quartz veins, and pegmatites; in hydrothermally altered pumiceous tuffaceous sediments.
It is found associated with Mordenite, heulandite, ferrierite.
The name refers to Antonio D'Achiardi (1839–1902), Italian mineralogist, whose son described the mineral.
Index entry. This entry combines official IMA/RRUFF species data with published physical-property data — a full written entry hasn’t been published yet.
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