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GEMS.
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The substance composing stalactites is worked like alabaster, and made into vases, cups, and other little articles.
XCIV.
TOURMALINE.
A gem remarkable amongst all others on account of its electric qualities.
Tourmaline
is often found amongst antique jewellery, but we do not know what name
the ancients gave to this stone, of which no description remains
relative to its physical properties. Equally ignorant are we as to the
etymology of its name, which, nevertheless, seems to have come to us
from India.
In 1717 some German travellers found it at Ceylon and brought it to Europe, calling it ascentrehker, because it especially attracted or repelled ashes.
In
1758 an Italian, the Duke of Bajo Caraffa, procured two in Amsterdam,
which he presented to the celebrated Buffon, who was the first to give
a scientific description of them.
Then they received the name of electric sciorlo, from the German sciorl, derived from Shorlaw, a Saxon village, in whose environs it was abundantly found. But the term sciorlo is now only applied to the black kind, the others being called tourmaline.
Tourmaline is found crystallized in pebbles of different forms. The crystals are rhomboidal, and
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