Gyrolite and okenite , found in Mumbai (formerly known as Bombay ), India — Photo: Kritzolina · CC BY-SA 4.0
Okenite
A calcium silicate forming fuzzy white 'cotton-ball' sprays of flexible needles inside basalt geodes.
Intro adapted from Wikipedia (CC BY-SA).
Okenite is an IMA-recognized mineral species in the silicate class, with the chemical formula Ca₁₀Si₁₈O₄₆·18H₂O.
It crystallizes in the triclinic crystal system (space group P-1).
Key properties: Mohs hardness 5; specific gravity 2.28–2.33; Vitreous to pearly luster; refractive index 1.525; optically biaxial.
IMA symbol Oke, grandfathered status — known before the IMA’s founding, named in 1828.
is commonly found in amygdules in basalts.
It is found associated with Zeolites, apophyllite, prehnite, calcite, quartz, \chalcedony.".
The name refers to the German naturalist Lorenz Ocken (1779–1851), of Munich, Germany, the mineral name later shortened.