TRAVELS IN BRAZIL, 



Note 2. 



In the mine of the guarda mor, Irmocenzio, on tlir 

 Serra de Cara^a, and particularly in the diamond district^K 

 gold crystals are not uncommon, and several were shown 

 to us which may altogether be referred to two original 

 forms, Th^y are either octahedrons, partly perfect, partly 

 blunted at the corners, or at the corners and edges, and 

 partly tetrahedrons, the edges of which sometimes appear 

 truncated. Twin crystals, or similar conjunctions of single 

 crystals, are sometimes observed. In general, gold is found 

 in Brazil of ail the colours and forms hitherto known* 

 The first are bright yellow, brass and greyish yellow, in 

 which last the alloy of silver is so considerable, that the 

 gold-dust acquires a brownish tarnish by oxydation. It is 

 affirmed that platina is sometimes mixed with it, but we 

 oin'selves could never ascertain it. With respect to the 

 forms, the loose, roundish, or flat grains are the most fre- 

 quent, but other configurations are also met with. It is 

 washed out of the sand of several rivers, in particles 

 scarcely visible to the naked eye, among which we observed 

 quartz-sand, partly pure, partly mixed with much mica and 

 lime ; we have before us some gold-dust said to be from 

 the capitania of Saint Paulo, which contains also magnetic 

 iron-stone, with grains of cinnabar. 



The tapanho-acanga, or the iron-stone flotz, subordinate 

 to the quadersandstein formation, is the secondary bed of 

 the gold, in which its abundance in all forms is astonishing ; 

 whereas in Europe this iron-stone formation,^ considered as 

 a whole, and in its separate members, is very extensive, 

 for instance, in the kingdom of Bavaria, as we have already 

 observed, without containing any traces of gold. In the 

 quartz strata, and beds of the clay^slate, and of the quartz 

 and iron mica-slate, the gold is particularly beautiful, den- 

 dritically and reticularly knitted, and aggregated in rows. 



