Blog Apophyllite and Stilbite
Rocks and Minerals Information Sheet R004


Crystal Structure of a Zeolite Zeolites are microporous, aluminosilicate.

The term zeolite was originally coined in 1756 by Swedish mineralogist Axel Fredrik Cronstedt, who observed that upon rapidly heating the material Stilbite, it produced large amounts of steam from water that had been adsorbed by the material. Based on this, he called the material zeolite, from the Greek zeo, meaning to boil, and lithos, meaning stone.

Apophyllite grows as clusters of crystals protruding into lava flows and also occurs in association with other zeolites (typically Heulandite and Stillbite) in the cavities in Basalt and Limestone and also in some hydro-thermal mineral veins some of which can be found in Scotland, Germany and India. It is sometimes known as Fluorapophyllite or Chloroapophyllite as it often contains chlorine instead of fluorine. olours are lovely pastel shades of green and other colours as well as white. Most of the current pieces featured in my collection are in fact Indian in origin. Chemical Group: Hydrous Silicate

Hydrous silicate again and usually what is called a monoclinic crystal system (whose members have three unequal axes two of which intersect at an oblique angle and the third perpendicular to the other two ). Colours range from white through pinks, red and brown being transparent or transluscent and they frequently have wonderful coffin shaped crystals. Frequently occuring with Stilbite in cavities in sedimentary rocks, basalt and hydro-thermal veins. Sometimes appearing in wonderful stalactitic formations such as the example in thestock list. Found in Scotland, Germany (Ider-Oberstein and Hazz) and India.

Another monoclinic crystal as Heulandite forming sheaf like aggregates of twinned crystals with colours from white through yellow to pink and occasionally brick red. Usually transparent. Found in Tertiary basalt lavas in Co. Antrim Ireland, hydro-thermal veins in Skye Scotland, Iceland, France, Nova Scotia, Jalgaon India.
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