ft 94 Elements of Mineralogy. 



xin zwltter ; the black are reckoned the rich- 

 eft, and afford about 80 percent, of tin ; they 

 all contain a mixture of iron. 



7. The ore called iveifs zingraupen is that 

 which was mentioned under the calcareous 

 genus by the name of tungften ; it contains 

 no tin. When any arfenic is found in tin, it 

 proceeds from the matrix, for tin itfelf is 

 never mineralized by it ; and for the fame 

 reafon zinc is fometimes found in tin. 



8. The fpecific gravity of this ore is 6,75. 

 Mem. Stock. 1778, p. 321. 



III. VARIETY. 



Reddifh or reddijh yellow Tin Ore, Garnet Tin 



Ore. 



9. This confifts of fmall cryftals femi- 

 tranfparent or opake, and fometimes it is 

 found of a fpherical form, ftriated, and re- 

 fembling haematites or zeolyte; its fpecific 

 gravity is from 5 to 5,8 j it contains more of 

 iron than of tin. 



IV. VARIETY. 



Tin Stone> Zinjlein of the Germans^ Tinberg 

 of the Swedes. 



10. The preceding varieties confift for the 

 moft part of metallic particles ; the prefent, 



chiefly 



