Idocrase Enlarge
[Undated]
Exotic Mineralogy
CXX
Silex Idocrasis

Idocrase

Such brilliant specimens of Idocrase I believe are not to be found in any other than Mr. Heüland’s cabinet. The Irish variety, figured in British Mineralogy, is so unlike these, that they would hardly be recognized as the same species, were not intermediate varieties, often before us. The green specimen is from Ala, in Piedmont; it is accompanied by green mica: the other from Locana, in the same country.

I have added a single crystal from Wilui, Baikal: it approaches in dullness to the Irish, but is of a greener and more intense colour.

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