F. A. Genth—Contributions to Mineralogy. 309 
This brief review contains, I believe, all that has been com- 
municated with reference to the occurrence and composition of 
tellurium minerals in this country, and it will be seen from it 
mineral, which may be native tellurium. 
My analyses had to be made with the cleanest that could b 
pieces, but they were at once, as far as possible, repeated, when 
I received through the kindness of Dr. I. Adelberg and Messrs. 
Louis Beckers and Jas. B. Hodgkin of New York, and E, Bal- 
bach, Sr., of Newark, N. J., specimens from the Stanislaus 
mine, which gave me minute quantities of perfectly pure alta- 
ite, the highly auriferous hessite (petzite), and of the new and 
interesting mineral calaverite. : 
e tellurium ores of the Stanislaus mine occur in talcose 
and chloritic slates, associated with quartz, dolomite, ? apatite, 
anium mineral, titaniferous iron, pyrites, chalcopyrite, 
perfectly pure “ae for analysis, 
a. Petzite and Hessite—Of all the tellurium minerals, which 
have been cuando California, that variety of tellurid of 
