black
and resinous, the interior forming a crystalline ker. nel, vitreous and
lamellar, like the diamond; it is reduced to powder, and used for
polishing and assisting in the cutting of the diamond. The largest
specimen of the compact diamond weighs about 46 carats, and belongs to
Mr. Hem-erdinger; and a compact diamond in the Museum of Natu-' ral
History at Paris, weighing about seventeen carats, is •valued at
fifteen hundred francs. The original bed of the diamond is not yet
known, and on this point opinions are much divided. In the East Indies
we find it in a conglomerate of sandstone, consisting of quartz
grains, and disintegrated by the ferruginous sand ; and in the
mountain chain Ralla-Malla, in Hindostan, between 95° and 98° E. L.
Some of the celebrated diamond mines consist of a breccia from
argillaceous slate, quartz, lime, and sandstone; the boulders and the
sand of deserts and rivers yield diamonds mostly rounded or in a
granular form. The richest diamond mines are those of Roalcorda, at
the junction of the riveis Bimah and Ristna; Golconda, along the shore
of the Pennar, Sumbhulpra, and Bundelkened, in the neighborhood of
Pannah, where one thousand laborers are kept employed. Visapur,
Hydrabad, &c, on the island of Borneo, likewise yield diamonds;
and, according to Jameson, diamonds were found in the Indies in the
coal formation.
In
Brazil, they were discovered, in 1728, by chance, having been always
thrown aside with the flint and other refuse of the washings of gold,
until an inhabitant, who had some knowledge of rough diamonds,
collected a large number, and carried them to Portugal, and acquired
by their sale a great fortune. Another, who was informed of the
operations of the first, shared an equally good fortune. The
government's attention was drawn to the matter, and it was declared, in
1730, that all diamonds found there belonged to the crown.
