Epistilbite
Image: Robert M. Lavinsky (CC BY-SA 3.0)
Mineral NameEpistilbite
Chemical FormulaCaAl₂Si₆O₁₆·5H₂O
Mohs Hardness3.5
Crystal Systemmonoclinic
Lustervitreous
Streak Colorwhite
CleavagePerfect on {010}, good on {100}
Fractureuneven
Specific Gravity2.22
Colorswhite, colorless, yellowish, reddish, pinkish
Transparencytransparent
Type LocalityJalgaon District, Maharashtra, India
Mineral GroupSilicates (Zeolite Group)
Usescollector, industrial (as a zeolite)
Associated Mineralsstilbite, heulandite, scolecite, apophyllite, calcite, quartz
Rarityuncommon
Description
This specimen features a cluster of white to translucent, tabular to blade-like epistilbite crystals, exhibiting a vitreous luster and forming an aesthetic aggregate.
Geological Context
Epistilbite is a zeolite mineral that typically forms in the amygdales and cavities of basaltic volcanic rocks, resulting from the low-temperature hydrothermal alteration of primary minerals.
