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p. Basalt, Trap, Wakken, Mullen, Krag ; colour 

 blackifh green, and fometimes deep black ; cryf- 

 tallized in fix and eight fided prifms, cuneated on 

 the ends ; it's furface fhining on being broken ; 

 when longitudinally, the lamellae are parallel. Anal. 

 Argill 15. Silex 50. Carbonate of lime 8. 

 Iron 28. Magnefia 2. Bergman. Conf. Wi- 

 thering. 



q. Calp y flaty, amorphous. Anal. Argill, filexj, 

 and iron, with fifty per hundred weight of carbo- 

 nate of lime. Kirwan. 



r. Argillaceous Schistus, Argillite, Killas, Gra- 

 pholite; colour bluifli or bluifh grey, purplifh or 

 black ; amorphous and flaty. Anal. Argill 25. 

 Silex 60. Magnefia 9. Iron 6. And fome pe- 

 troleum. Kirwan. 



f. Novaculite, Turkey hone, amorphous and 

 flaty. 



F. SILEX, is rough to the touch, cuts glafs, and 

 fcratches metals ; is infufible, and infoluble in 

 molt acids, except the fluoric, forming Derbyfhire 

 fpar 3 foluble in alkalies, with the affiftance of heat 

 forming glafs ; found in moft ftones that ftrike 

 fire with fteel. 



a. Diamond^ cryftallized in oclohedrons* and 

 their varieties ; and in dodecahedronst and icofa- 



* Ofiohedrons, ex oxTv, eight ; et bafis. 



$ Dodecahedral, ex Sw&xa, twelve ; et c5^«, bafis. 



hedrons 



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