Vorkommen von Palladium und Platin in Brasilien. 43o 



Er schreibt: »This place, apparently so insignificant, proved 

 one of the most interesting, in a mineralogical point of view, 

 which I had hitherto visited. 



It is called Largos and also bears the name of Oro Branco 

 (White Gold) in allusion to a granulär substance, not unlike 

 gold in size and weight, found in a gold-washing in the bed of 

 the stream. This substance, which has since been proved to be 

 platina, was discovered many years ago in the cascalhao below 

 the vegetable earth and incumbent of the solid rock, accom- 

 panied with gold and black oxide of iron. 



From these circumstances the people judged it to be gold 

 united with some other metall, from which it could not be 

 separated and, as the quantity of real gold found was small, 

 and the withe gold, as the called it, was not known to be of 

 value, the work w^as gradually abandoned. 



1 procured a specimen of the substance: it appeared 

 accompanied with Osmium and Iridium, and was in rougher 

 grains than the platina brought from the province Choco, which 

 latter circumstance may be ovving to its not having been tritu- 

 rated with mercury. Now that the substance is known to be 

 platina, it is doubtful wheter the work might be resumed with 

 advantage, as the demand for that article is at present so small, 

 that the quantity sold would hardly pay expenses. 



Near this place is a work, called »Matta dos Cavallos«. 



hl einer beigefügten Routenskizze gibt Mawe den Fundort 

 genau an und wurde erst kürzlich daselbst das Pt wieder auf- 

 gefunden. 



A. V. Humboldt hebt hervor, daß die beiden Geologen 

 und Reisenden v. Eschwege und Pohl der Ansicht hinneigen, 

 »daß das Gold, der Eisenglimmerschiefer, die Diamanten, die 

 Euklase (und Topase), das Platin und Palladium, welche dem 

 angeschwemmten Erdreiche Brasiliens eigentümlich sind, von 

 der Zerstörung der großen chlorithaltigen Quarzformation (dem 

 Itacolumit) oder einer eisenschüssigen Schicht (dem Itabirit) 

 abzuleiten seien, welche von den AUuvionen bedeckt sind.« 



Die Gelehrten v. Spix und v. Martius passierten auf dem 

 Wege von Sahara nach Diamantina, über Conceicao gehend, 



