164' TRAVELS IN BRAZIL. 



From the Morro de Gravier the descent is but 

 inconsiderable to reach the beautiful Fazenda Ca- 

 pao, and a quarter of a league farther to the farm 

 of Lana. This is the district in which the well- 

 known Brazilian topazes are found. The basis of 

 the rock is flexible quartz ; yet it is seldom in its 

 usual form, but more frequently in the variety 

 called by Eschwege, iron mica-slate. Incumbent 

 on it are immense layers of a modified mica, which 

 might be denominated earthy talc. They form low 

 rounded hills, in which those precious stones are 

 found in three different places, but chiefly near the 

 two abovementioned farms. Immediately behind the 

 Fazenda Lana there is a hill which, on one side, for 

 a considerable breadth and to a height of sixty feet, 

 is so softened by rains, and by water conducted 

 upon it by art, that it is like a marsh, and without 

 changing its position in parts, sinks lower all toge- 

 ther. We found the owner and his slaves just then 

 busy in looking for topazes. The soil is thrown 

 up into long heaps with shovels, and washed by 

 means of water conducted over it into a narrow 

 channel, with some wooden lattices fixed in it, so 

 that only the more solid parts remain behind, which 

 are then broken with hoes and with the hands in 

 search of topazes. These harder parts of the de- 

 composed formation are the fragments of white 

 quartz, often quite friable, sometimes mingled with 

 detached rock-crystals, and are often accompanied 

 with a white or brown ferruginous porcelain earth. 



