Stellerite crystals with some chabazite-Ca on the matrix (5.5 × 4 × 2.5 cm). Found from Takat, Imilchil, Midelt Province, Drâa-Tafilalet Region, Morocco — Photo: Ivar Leidus · CC BY-SA 4.0
Stellerite
A rare calcium zeolite named for explorer and naturalist Georg Wilhelm Steller.
Intro adapted from Wikipedia (CC BY-SA).
Stellerite is an IMA-recognized mineral species in the silicate class, with the chemical formula Ca₄(Si₂₈Al₈)O₇₂·28H₂O.
It crystallizes in the orthorhombic crystal system (space group Fmmm). It is a member of the Stilbite structural group.
Key properties: Mohs hardness 4–4.5; specific gravity 2.13; typically white or orange or pink; white streak; vitreous luster; optically biaxial.
IMA symbol Ste, IMA status: approved, named in 1910.
Lines cavities and fracture surfaces in volcanic rocks altered by hydrothermal solutions.
It is found associated with Zeolites, prehnite, tridymite.
The name refers to Georg Wilhelm Steller (1709–1746), discoverer of the Komandorskiye (Commander) Islands, Russia.
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