Diamonds sf Brazil. 'J 



Farm abandoned the mountains, and formed great eftabliflimfnts in the river of Toucan - 

 Urnen, which flows through- the valleys of this chain, and is near ninety leagues in length. 

 It was found by examination and digging, that the whole furface of the ground, imme- 

 diately beneath the vegetable flratum, contained more or lefs of diamonds, dlffeminated 

 and attached to a matrix ferruginous and compaft in various degrees, but never in veins, 

 or in the divifions of geodes. 



Attempts were made at fird to prohibit the working; but the aSivity of indivirluals 

 who infringed the order of Government, and fent home diamonds by the fliipping from 

 Brazil, under the denomination of oriental diamonds, induced Government to eftablifli a 

 farm. The firft farmer was Ri{herto Caldera, a Paulift, with the condition that no more 

 than 600 negroes (hould be employed in this work. This condition has always been 

 evaded ; for the number of (laves employed are from fix to eight thoufand : and this num- 

 ber was fcarcely diminiftied when the Portuguefe Government, to put an end to this fraud 

 and the depreciation in price of diamonds proportional to the quantity brought to market, 

 c.iufed the undertaking to be carried on for its own account. But at prefent, from other 

 confiderations, it is farmed again to individuals. Notwithftanding the great profits which 

 enter the royal treafury, it is certain that the inhabitants of the province are greatly injured by 

 it, becaufe the Diflricl of Diamonds being continually enlarged, has condemned to dcRruc- 

 tive repofe immenfe tra£ls very rich in gold. 

 Let us now proceed to the diamonds. 



The figure of the diamonds of Brazil varies. Some are oiflahedral, formed by the 

 union of two tetrahedral pyramids. This is the adamas oEia'edrus turbintHus of Wallerius, 

 or the odlahedral diamond of Rome de I'lfle. Thefe are almoft always fqund in the cruil 

 of the mountains ; others are nearly round, whether by a peculiar cryftalliiation or by 

 rolling. They refemble thofe oriental flones which the Portuguefe and the natives of 

 India call reholudos, which fignifies rolled. And laftly, others are oblongs and appear to 

 me to be the adniiias hcxaedrus tahellatus of W-llerius. The two lad are ufually found 

 in the beds of rivers and broken places of their banks. 



Diamonds are alfo found, as I have remarked, in the cruft or external covering of moun- 

 tains. Thefe mafles are formed of a bed of ferruginous fand, with rolled flints, forming an 

 ochreous pudding-ftone from the decompofaion of emery and muddy iron-ore ; it is 

 called cnfcalho, and the beds or ftrata taboleiros. Thefe tabokiros have different names, 

 according to their fituation or their nature. When the flratum is horizontal, and in the 

 plane of the bed of the river, it is properly a t^boleiro s but if it rifes in banks, it is called 

 gopiara ; laftly, if the pudding-fiohe contains much emery, it is then denominated /a^j/;- 

 hua caugn in Brazilian, that is to fay, black-ftone, or iron-ftone. 



In fome places the cofadho is uncovered ; in others, it lies beneath a kind of vegetable 

 muddy earth, humus damafcena Linn, or beneath a reddifli fat fand, which fometimes con- 

 tains rounded flints. This happens in the returns of the mountains, or upon the banks of 

 great torrents. This fand is called pifarra. The bank or flratum beneath the cnfcalho is 

 either fliiftus rather fandy, or the folid bog-ore of iron. It is likewife in the caJcMo that 

 gold in fpangles and in pyrites is found ; the former of which is in my opinion afforded 

 by the dccompofition of tlic auriferous pyrites. For the gold in veins lias anollier form, 

 Vol. I. — /\rRiL «797. E and 



