^06 



TRAVELS IN BRAZIL. 



unctuous quartz, with very small shorl crystals, is em- 

 bedded. The pearly mica is particularly beautiful on this 

 bed. It is of an emerald-green colour, through which the 

 pearl-grey shines in many places, of a strong lustre, and 

 very bright mother of pearl hue. On the piece now before 

 us, there are small dark leek-green transparent crystals of 

 electric shorl, in various directions, in which, besides very 

 small grains and particles of pure gold, greyish white 

 apatites crystallised are embedded in the low six-sided 

 prisms, truncated at both ends. The crystals are small, 

 and the rifts of the pearly mica are not unfrequently 

 covered with brown oxyde of iron. Quartz seems to be a 

 constituent part of this auriferous bed. It is of a smoky 

 grey colour, which is tinged reddish grey, by oxyde of 

 iron. In this quartz are also embedded acicular crystals of 

 a dark green electric shorl. It is partly full of little 

 drused cavities, which are covered with a dirty apple-green, 

 probably caused by copper nickel. This quartz also con- 

 tains arsenical pyrites, as it seems in blunt-edged pieces, 

 surrounded by brown oxyde of iron, in which native gold 

 is embedded in very small cubes. It has a silvery colour, 

 approximating to tin, and no particular marks of distinc- 

 tion. Mr. Von Eschwege (p. 20.) observes, that on this 

 bed iron pyrites and antimony also grow, on which, as 

 these fossils did not fall under our observation, we have 

 the less reason to make any remark, as their appearance 

 cannot be disputed on geognostical principles. 



