mineral has occasionally been cut and polished as a gem-stone, but
rather as a matter of scientific curiosity, than with a view to its
introduction into jewellery. It is, in fact, a rare mineral,
occasionally found with Topaz at Villa Rica, in Brazil. It is also
known to occur with Beryl, on the River Sanarka, in the Urals.
is always found in crystals which exhibit perfect cleavage, and perhaps
the most curious feature of the stone is its excessive
brittleness—whence, indeed, the name " Euclase," from eu and klao. Its
colour is generally a pale straw, passing in some specimens into blue
and green. The mineral is trichroic, and possesses considerable lustre.
In its chemical relations it stands closely related to the Emerald.