336* DOMAIN IV. TALCOUS. 



markable pierre de come of Saussure, here called 

 Saussurite, in honour of that great observer. 



Patrin is perhaps the only professed writer on 

 mineralogy who has enlivened his subject by 

 variety of illustration ; and as his work will pro- 

 bably never appear in the English language, his 

 descriptions, which often contain anecdotes de- 

 rived from his own extensive travels, are given 

 with the less hesitation. 

 Patrin's " Serpentine owes its name to its colour : it 



account. 



is generally green, often spotted with white, 

 yellowish, brown, and sometimes reddish marks, 

 which gives it some resemblance to the skin of 

 serpents. Its green colour is owing to iron, 

 which is abundant in it, and but little oxygi- 

 nated*. 



" It is generally opake ; but some of its parts 

 are occasionally semi-transparent. Though not 

 very hard, it receives a fine polish, which has an 

 unctuous appearance, like jad. 



" Serpentine is a primitive rock; the forma- 

 tion has been a little posterior to that of massive 

 granite, for it is very rare to find them united. 

 It has been contemporary with that of micaceous 

 and calcareous schisti, with which it is some- 

 times seen confounded, whether in the same or 



* This seems rather doubtful. 



