1838.] .MAMOND WASHINGS. 55 



pan J eight hundred pounds, of the value of one million ster- 

 ling. 



The matrix, or original repository, of the diamond of Bra- 

 zil, is brown iron ore, occurring in beds of slaty quartzose 

 micaceous iron ore. or composed of iron-glance and magnetic 

 iron ore. The diamond mines were originally discovered in 

 1728, in the district of Serro-do-Frio. The most celebrated 

 mine is that of Mandanga, north of Rio Janeiro, on the Jigi- 

 tonhonha. The river, which is from three to nine feet deep, 

 is made nearly dry, by drawing the water off with sluices at cer- 

 tain seasons : and the diamond gravel, here called cascalho, is 

 removed from the bed of the stream, to be washed elsewhere 

 at leisure. The gravel is always collected in the dry season, 

 and washed during the rainy. For the latter purpose, a stream 

 of water is admitted into a number of boxes containing the 

 cascafho, beneath an oblong shed. Attached to each box is 

 a negro washer, and there are inspectors placed at regular 

 distances, on elevated stools. Great precautions are taken to 

 prevent the concealment of the diamonds by the washers, 

 and when one is discovered, the finder is required to rise up 

 and exhibit it. When the negro is so fortunate, which very 

 rarely happens, as to discover a gem weighing seventeen and 

 a half carats,* he recovers his liberty. The earth of the 

 bottom lands on either side is as rich in diamonds as that in 

 the channel of the river. All the diamonds found in the dis 

 trict of Serro-do-Frio, are deposited, monthly, in the treasury 

 at Tejuco. The amount thus delivered, from 1801 to 1806, 

 has been estimated at about eighteen or nineteen thousand 

 carats, annually. 



There are fine mines of diamonds on the Rio Pardo, and 

 at Tocaya, in the district of Minas Novas, near the confluence 

 of the Jigitonhonha and the Rio Grande. The largest dia- 

 monds, however, obtained in Brazil, are found in the cantons 

 of India and Abaite. 



In addition to these great mineral treasures, there are 



* A diamond of that size is worth £2400 sterling, not far from $10,000, fed- 

 eral currency. 



