153 



TAB. CLXXX, 



SILEX Mica. 

 Mica. 



Gen. 4. Silex. 



Syn. Mica, Muscovy Talc. Kirwan, v, 1. 210, 

 Mica. Haiiy, v. 3. 208. 

 Mica membranacea. M. laminosa, %c. Linn* 



ed. 13. /. 3. 58. 

 Glimmer of the Germans. 



Mica, i^ikaos, or [unpos, has been long noticed as a glittering 

 substance, and often serves to countenance the idea that 

 our streets are paved with gold and silver. It is one of 

 the first things that takes the attention when fragments of 

 the granite stones from Aberdeen are lying in our streets for 

 paving or building, which has been frequent since the 

 improvement of forming such durable stones into shape for 

 that purpose ; an improvement not much above half a 

 century old. It soon becomes as it were familiar to the 

 Mineralogist by its frequent occurrence ; yet there is some_ 

 confusion with regard to its identity, as it has been con- 

 founded with Talc: see tab. 182, 183, and 184, 



The present specimen has most of the characters belong- 

 ing to this very curious substance ; it has signs of the in- 

 tegrant molecule, a triedral prism, whose base is equi- 

 lateral, and of the rhomboidal prism formed of two of these 

 its primitive, with various lengthened rhomboids, hexagons, 



