Scolecite

scolecite

prehnite

heulandite

stilbite

Images

Formula: Ca(Si3Al2)O10.3H2O
Tectosilicate (framework silicate), zeolite group
Specific gravity: 2.24 to 2.31
Hardness: 5 to 5½
Streak: White
Colour: Colourless, white, pink, salmon, red, green
Solubility: Soluble in common acids
Common impurities: Na,K
Environments:

Metamorphic environments
Hydrothermal environments
Basaltic cavities

Scolecite occurs in basalt, andesite, gneiss, and amphibolite, in contact metamorphic and in hydrothermal environments. It is associated with other zeolites, calcite, quartz and prehnite (Dana).

Localities

At the Marron Volcanics of the Olalla Area South-Central British Columbia, Canada, Compact masses of colour-zoned (salmon-pink-white) acicular scolecite completely fill vesicles to 10 cm long in the road cuts and the upper areas at Yellow Lake. Some terminations are mesolite, but the bulk of this type of occurrence consists of scolecite (R&M 96.6.524).

In Eritrea scolecite has been reported in weathered basalt, associated with stilbite and calcite (DHZ 4 p375).

Near a pegmatite at Valle Maggia, Switzerland, scolecite occurs in crevices in biotite gneiss associated with K-feldspar variety adularia, epidote and chlorite (DHZ 4 p375).

On the Isle of Mull, Scotland, UK, scolecite occurs in profusion in basaltic cavities, and is often the final product of the sequence
albitechloriteepidoteprehnitescolecite
though in some cavities heulandite succeeds scolecite (DHZ 4 p375).

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