FP, A. Genth’s Contributions to Mineralogy. 253 
deposites upon itself a coating of the latter, or in the same man- 
ner, in which the green tourmaline, of Chesterfield, Mass., sur- 
rounds a nucleus of the red. I do not think that ever anybody 
considered the green a pseudomorph of the red one? 
12. Wolfram. 
I have examined the wolfram, which forms the nucleus of the 
thombic tungstate of lime. 
Only one crystal has been observed yet, which shows the 
planes J, 27, 47 and 13. Sp: gray. at 25° Cels. =7:496. It contains: 
Tungstic acid, - - - - - 75°79 
Oxyd of iron, - - - « - - 19°80 
xyd of manganese, - - - - - 5365 
Lime, - - - - - - - 0-32 
Binoxyd of tin, - - - - : - trace 
101-26 
This corresponds with the formula: 4FeO, WO,+Mn0, WO,. 
13. A few observations on the occurrence of Gold. 
_ Much has been said and written about the occurrence of gold 
I veins and elsewhere and the formation of the same, but com- 
The gold obtained from the disintegrated diorite is generally 
smooth and rounded as if it was water-worn. This cannot be, 
however, because it lies still in its original, but only altered 
ix, and has not been subjected to any attrition by water and 
