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yellowifh fmoke grey, or black grey colour ; 

 cryftallized in double trihedral pyramids ; in. 

 maffes of various fizes, in ftrata of chalk ; when 

 broken, exhibits a conchoidal furface, and the 

 fragments are fharp edged, but of an indetermi- 

 nate fhape ; femi-tranfparent. Anal. Silex 60. 

 Argill 18. Lime 2. Wiegleb. 



g g. Horns tone, Siliceous Schistus, or Basanite^ 

 Hornslate. Petrosilex. Cryftallized in hexahe- 

 dral prifms, with or without pyramids, in double 

 trihedral pyramids, in cubes ; amorphous, com- 

 pact ; flaty ; colour various, yellowifh white, blu- 

 ifh, pearl, green inclining to red, brownifh, rofe 

 colour, blackifh brown. Anal. Hornstone. Silex 



72, Argill 22, Carbonate of lime 6. Kirwan. 

 B as anite. Silex 73. Lime 10. Magnefia 0,046. 

 Iron 3. Coal 5. Weigleb. Hornslate. Silex 



73. Argill 24. Iron 3. fViegleb. 



h h. Jasper, Egyptian Pebble, found in irregu- 

 lar hexahedral prifms ; amorphous, in large maf- 

 fes and nodules, and of all colours. Anal. Silex 

 54. Argill 30. Iron 16. Delametherie. 



i i. Porcelanite, Porcelain Jafper, of a pearl 

 grey, or lavender blue colour ; found in compact 

 layers. It's furface, when newly broken, is a little 

 fkinny and gibbous. 



k k. Heliotr opium, Bloodstone, of a leek green 

 colour, with blood-red fpots or veins ; is femi- 

 tranfparent ; exhibits a conchoidal furface when 

 broken. 



R 2 It 



