MINERALOGY, 249 



any of it. Befides this, there are alfo fome 

 fibrous particles in it, and fomething that 

 reiembles a calcareous fpar : This however 

 does not ferment with acids, but melts as 

 ealy as the Hone itfelf, which becomes a 

 black folid glafs in the fire. By calcina- 

 tion it becomes red, and yields in afiays 12 

 or more per cent, of iron. No other fort of 

 pre is to be found in it, unlefs new and 

 then fomewhat merely fuperficial lies in its 

 fiflures ; for this ftone is commonly, even to 

 a great depth in the rock, cracked in acute 

 angles, or in form of large rhomboidal dice. 

 It is employed at the giafs-houfes, and added 

 to the compofition of which botdes are 

 made. By the Germans it is called Sckwach 

 or §ch r s:crtsfiein\ at the Swedifh glafs-works, 

 'Trappjkiol^ ¥egelfkicl^ or Swartjkiol - 9 and at 

 Jarliberg in Norway, Blabeft. In the air 

 it decays a little, leaving a powder of a 

 brown colour •, it cracks commonly in the 

 fire, and becomes reddifh brown if made 

 red hot. It is found 



1. Of coarfe chaffy particles, Pcrticulis ma- 

 joribus acercfis. 



a. Dark grey, from the top of Kinne- 

 kulle in the province of Weilcrg^tt- 

 land. 



b. Black, from Stallberget at Gfcerfilf- 

 verberget in the province of Dalarne. 



2. Coarfe-grained, Particulis mcjoribus gra- 

 nulatis. 



a. Dark grey, from the uppermost flra- 

 tnm at Hunneberg in Weftergottland. 



b. Reddifh, from Bragnas in Norway. 



c. Deep brown, from Gello in Norway. 



3. Of 



