NOME XXVII. LIME-STONE, WITH SILEX. 

 HYPONOME I. 



Massive. 



HYPONOME II. 



Schistose. 



NOME XXVII. LIME-STONE, WITH SILEX. 



[BERTHOLITE, from Berthollet, 1800.] 



Concerning the calcareous stones Mr. Kirwan 

 observes, that " when mixed with siliceous par- 

 ticles in considerable proportion, they effervesce 

 with acids but slightly and slowly, and their 

 fracture tends to the conchoidal, but often also 

 to the earthy; of this we have a remarkable 

 instance in Leske, s. 229. Its lustre, 0. Hard- 

 ness, scarcely 9. Fragments, 3; which indi- 

 cates the siliceous ingredient. Its sp. gr. only 

 2,254 ; which shows it to be of the nature of 

 sand-stone. Heated to 141, it did not form a 

 lime, nor did it melt. When the lime-stone is 

 of the granular kind it has more lustre, and is 

 much heavier, see Leske, s. 1098. But when 

 the particles of silex are in a smaller proportion, 

 or not purely siliceous, the lime-stone presents 



