544 DOMAIN TI. CARBONACEOUS. 



MODE I. GRAPHITE. 



Characters. Texture, fine grained, but sometimes coarse, 

 schistose. 



Hardness, cretic. Fracture scaly foliated, some- 

 times slaty and uneven, sometimes rather con- 

 choidal. Fragments amorphous, rather sharp. 



Weight, carbonose. 



Lustre, metallic. Opake. 



Colour, somewhat leaden, which occasioned 

 the vulgar, but very improper, name of black 

 lead. 



When pure, it usually contains about 90 parts 

 oxyd of carbon, with 10 of iron ; but the foreign 

 kinds are often contaminated with large mixtures 

 of argil and silex, which renders them unfit for 

 the usual purposes of writing and drawing. 

 Sites. The best is that found at Borrodale, in Cum- 



berland ; a mine which has long supplied the 

 world with this valuable article ; but the French 

 have lately succeeded in the fabric of an arti- 

 ficial kind. Graphite has also been recently 

 detected in the southern parts of Scotland, with 

 a singular kind of coal, called columnar, because 

 it appears like little basaltic prisms, 



