340 DOMAIN IV. TALCOUS. 



The softest is foliated, and its specific weight 

 exceeds 3000, which is the weight of oriental 

 jad. It is this softest variety which the best 

 resists the action of fire. 



(f Some of the blocks found in the valley of 

 Chamouni present a green serpentine, marbled 

 with white, like the serpentine of Saxony ; others, 

 - a green serpentine also, but mixed with shining 

 plates of green talc, threads of asbestos, and of 

 brilliant and golden amianthus, with laminar 

 crystals in the form of flattened parallelepipeds. 

 These crystals have neither the hardness of 

 schorl, nor the characteristics of hornblende; 

 they melt into a white amel, while hornblende 

 always gives a black glass. The plates of green 

 talc are infusible; and the serpentine which 

 constitutes the base of the stone melts, in bub- 

 bling and emitting little sparks. 



" These fragments proceed from some hills, or 

 considerable masses, which have been destroyed 

 by time. Saussure saw, near Chiavenna, in the 

 country of the Grisons, entire mountains of ser- 

 pentine and ollite, which were only heaps of in- 

 coherent blocks. 



" The summit of the mountain of Garda, near 

 Genoa, is composed of a serpentine, which Saus- 

 sure has called granular : it is of a deep grey 

 green, with unequal fracture, dull, earthy, af- 



