104 DESCRIPTIONS OF MINERALS. 
in Hilore. In Borneo, they are obtained on the west side of 
tne Ratoos Mountain, with gold and platina. The Brazilian 
-mines were first discovered in 1728, in the district of Serra 
do Frio, to the north of Rio de Janeiro ; the most celebrated 
are on the river Jequitinhonha, which is called the Diamond 
ltiiver, and the Rio Pardo; seventy to seventy-five thousand 
carats are exported annually from these regions. In the 
Urals of Russia they had not been detected till July, 1829, 
when Humboldt and Rose were on their journey to Siberia. 
The river Gunil, in the province of Constantine, in Africa, 
is reported to have afforded some diamonds. 
In South Africa, where they were first discovered in 1867, 
they occur in the gravel of the Vaal River, and in the 
Orange River country. ‘The value of the diamonds obtained 
up to November, 1875, has been estimated as exceeding 
60,000,000 of dollars. ; 
In the United States, the diamond has been met with in 
Rutherford County, North Carolina; Hall County, Georgia ; 
also Franklin County, North Carolina; in Manchester, 
opposite Richmond, Virginia; also in Cherokee Ravine, 
Butte County, Forest Hill in El Dorado County (one weigh- 
ing nearly 5°62 grains), Fiddletown in Amador County, and 
in Nevada County, California; and on the coast of Southern 
Oregon. It has been reported from Idaho. 
The original rock in Brazil appears to be either a kind of 
laminated granular quartz, called itacolumyte ; or a ferru- 
ginous quartzose conglomerate. The itacolumyte occurs in 
the Urals, and diamonds have been found in it; and it is 
also abundant. in Georgia and North Carolina. In India, 
the rock is a quartzose conglomerate. The origin of the 
diamond has been a subject of speculation, and it is the 
prevalent opinion that the carbon, like that of coal and 
mineral oil, is of vegetable or animal origin. Some crystals 
have been found with black uncrystallized particles or seams 
within, looking like coal ; and this fact has been supposed 
to indicate such an origin. 
Diamonds, with few exceptions, are obtained from allu- 
vial washings. In Brazil, the sands and pebbles of the 
diamond rivers and kvooks (the waters of which are drawn 
off in the dry season to allow of the work) are collected and 
washed under a shed, by a stream of water passing through 
a succession of boxes. A washer stands by each box, and 
inspectors are stationed at intervals. 
