*« A SYSTEMO?. 



or agreeable, it is commonly confidered as 



a different fubftance. 



a. Blackifh grey, from the province of 



Skone. 

 i. Yellow femi-tranfparent, from France. 

 c. Whitifh grey* 

 d* Yellowifh brown* 



When the flints are fmall, they are in 



England called pebbles ; and the Swedifh 



failors, who take them as ballaft, call them 



ftngeL 



SECT. LXIII. 



§. Chert, Petrqfilex, Lapis Corneus. Th* 

 Hornftein of the Germans. 



Is of a coarfer texture than the preced- 

 ing, and alfo lefs hard, which makes it con- 

 fequently not (o capable of a polifh. It is 

 femi-tranfparent at the edges, or where it is 

 broke into very thin pieces. 



a. Chert of a flefh colour, from Carl- 

 Schakt, at the filver-mine at Salberg, in 

 the province of Weflmanland. 



b. Whitifh yellow, from Salberg. 



c. White, from Krifliersberg, at Nya Kop^ 

 parberget, in Weflmanland. 



d. Greenifh, from Preftgrufvan, at Helle- 

 fors in Weflmanland *. 



* There are not yet any certain characters known, by 

 which the Cherts and Jafpers may be diftinguifhed from 

 each other : by fight, however, they can eafily be difcerned. 

 viz. the former, or chert, appearing femi-tranfparent, and 

 of a fine fparkling texture, on being broken ; whereas the 

 jafper is grained, dull, and opaque, and has exactly the ap- 

 pearance of a dried clay : the chert is alfo found forming 

 larger or fmaller veins, or in nodules like kernels in the rock; 

 whereas the jafper, on the contrary, fometimes constitutes 

 the chief fubftance of the higheft and moll extended chains 



of 



