Minerals & Gemstone 480x104

Advertising Information

Spiky Epistilbite Spray

The Mineral epistilbite

Epistilbite is a rare member of the zeolite group. It has a very similar chemical makeup to Stilbite, and can be difficult to distinguish from Stilbite. Epistilbite is named from the Greek Epi which means "similar" and Stilbite, due to the similarity of this mineral to Stilbite. Epistilbite is not dimorphous with Stilbite, despite its prefix Epi which often implies a dimorph. Interestingly, Epistilbite it dimorphous with a different zeolite, the rare Goosecreekite.

Chemical Formula CaAl2Si6O16 · 5(H2O)
Composition Hydrous calcium aluminum silicate
Color Colorless, white, cream, tan, light yellow, light brown, gray. Rarely orange, orange-red, or pink.
Streak Colorless
Hardness 4
Crystal System Triclinic
3D Crystal Atlas
(Click for animated model) 
Crystal Forms
and Aggregates
Crystals are often prismatic, with distinct chisel-topped terminations. Also globular and in hemispherical, ball-like formations. Other habits in include thin, tabular crystals and groups, columnar, in radiating clusters, and in jagged, haphazard crystals.
Transparency Transparent to translucent
Specific Gravity 2.2 - 2.3
Luster Vitreous, pearly
Cleavage 1,1
Fracture Uneven
Tenacity Brittle
In Group Silicates; Tectosilicates; Zeolite Group
Striking Features Crystal habits and association with other zeolites.
Environment In air vesicles in volcanic basalt.
Rock Type Igneous
Popularity (1-4) 3
Prevalence (1-3) 3
Demand (1-3) 3

Epistilbite AUCTIONS


Epistilbite is not a common member of the zeolite group, and good localities are few. Some of the largest crystals come from Berufjördur, Iceland, at Teigarhorn and Fossárfell. Sharp Epistilbite crystal group and aesthetic balls on matrix come from several localities in Maharashtra, India, most notably at Jalgaon, but also at Pune, Nasik, and Ahmadnagar. Small crystals with red inclusions come from Osilo, Sardinia, Italy. In the U.S., colorless micro crystals are found in the Puu o Ehu Quarry, Kailua, Oahu Island, Hawaii.

Quartz, Calcite, Heulandite, Mordenite, Stilbite, Apophyllite, Celadonite

Stilbite - Different crystal formation.

epistilbite PHOTOS
DISCUSSIONView Forum | Post to Forum
Have a question about Epistilbite? Visit our Q&A Community and ask the experts!

To sponsor this page, click here.

Let us know how we can update this page
(Click for more details)
We strive for accurate content and locality information. If you feel any of the content is incorrect, or if you feel we are missing vital locality information, please fill out the form below so we can update the site. If you are requesting a locality be added, please only include significant locality occurences for the mineral.