FE. A. Genth—Contributions to Mineralogy. 
ure, from an ae of ateog nti rtain the greater 
as petzite, both sade would give only about 97 pr. ct. 
ratio between gold and tellurium (after deducting the silver as 
petzite) is 1: 42 or nearly 1: 
calaverite is therfore AuTe, high: in its pure state would 
have the composition : 
Au 
4, the 
4Te 
suggestions. Under t 
197 
256 
A comparison between the analyses of the calaverite and 
those of the GE neh sylvanite leads t 
name sylvanite, ¢wo distinct minerals 
most probable formula for 
44°47 
55°53 
are hci treated; one, the so-called “graphic tellurium,” 
for which the name ‘ sylvanite” may remain, and the “ weiss- 
tellur” and “gelberz.” 
The most recent and reliable analyses of these minerals were 
made on ood who found in the graphic tellurium 
Offenban 
Tellurium 
Antimon 
Gold 
Copper 
ea 
Of the varieties weisstellur and gelberz from Nagy 
g, he 
analyzed : I, long crystals of a white color; II, thick cin: 
Ms short yellowish crystals; IV and V, massive bronze-yellow 
ral : 
Tellurium ___._. 55°39 
Antimony ----- 2°50 
Lt Se aie 24°89 
miter 2 14°68 
Sing ON ees eo 2°54 
From these analyses it will be observ 
tellurium the amount of silver varies ogg very ae and a 
and | a trifle 
the nike f Fete ve exactly, w 
ages g had cae 
car posible variati 
p.c¢. 
v. 
51°52 4454 49°96 
5°75 854 3°82 
27°10 25°31 29°62 
747 1040 = 2°78 
wie 3i3t ieee 
ed that in the graphi 
315 
very interesting 
from 
Sa Bee 
