m A S Y S T E M 0 P 
or agreeable, it is commonly confidered M 
a different fubftance. 
a. Biackifh grey, from the province of 
Skone. 
1. Yellow femi-tranfparent, from France, 
c. Whitifli grey. 
Yellov/lfh brown. 
When the flints are fmall, they are in 
England called pebbles ; and the Swedifli 
failors, who take them as ballaft, call them 
ftngeL 
SECT. LXIII. 
Chert, Petrqfilex^ Lapis Corneus. Ths 
Hornjlein of the Germans. 
Is of a coarfer texture than the preced- 
ing, and alfo lefs hard, which makes it con- 
fequently not fo capable of a poiiih. 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 Weftmanland. 
h, Whitiffi yellow, from Salberg. 
c. White, from Kriftiersberg, at Nya Kop- 
parberget, in Weftmanland. 
d. Greenifti, from Preftgrufvan, at Helle- 
fors in Weftmanland 
* There are not yet any certain charaflers known, by 
which the Cherts and Jafpers may be diftinguiflied from 
each other : by light, however, they can ealily be difcerneda 
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 exadly 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 conftitutcs 
the^chief fubftance of the higheft and moft extended chains 
