The
central point of the mines here opened is the little city of Tejuco
(Diamantina), situated 134 leagues from Eio de Janeiro, and 240 from
Bahia. It is the residence of the general-intendant, and contains
upÂwards of six thousand inhabitants, all employed in excavating the
mines ; which at the beginning yielded abundantly : the first twenty
years it is calculated that about three million carats of
rough-diamonds were dug out ; but the product did not continue in the
same proportion ; it diminished gradually : in the five years from 1801
to 1806 they only yielded 23,135 carats ; and in the ten years from
1807 to 1817 but 18,000.
Other mines were discovered in 1839, not far from these, on a very high
mountain of the same province. There are also mines at Tibbigi, near
San Paulo, in the province of Goyaz ; in the plains of Cubaja ; in the
river of Audaya ; in that of Malkoverde, and also in Brazil.
BRILLIANT.
In Italy they generally denominate that diamond a " brilliant " which is cut on every side in many facets.
With
us, then, the brilliant is a diamond rendered brilliant, that is,
worked on the wheel to give it in certain proportions planes or facets,
which, according to the laws of optics, reflecting back luminous ray-,
cause the gem to shine with great brilliancy.
It is not improbable that in a very remote period the Indians understood the method of polishing the diamond.
