(28 ECONOMIC GEOLOGY 
tin lodes and at higher levels. The main production in 
tecent years has been in the United States, which had an 
output in 1924 of 13,000 tons; France was second with 
10,000 tons; England produced 3200 tons from the Cornish 
copper mines, 
BisMUTH 
Bismuth (Bi; at. wt, 208; sp. gr., 9-8; melting-point, 
520° F. ; it expands 2-3 per cent. of its volume on solidifica- 
tion) is a white hard brittle metal, which is the most strongly 
diamagnetic of the elements. It is chiefly found native or 
as the sulphide, Bi,S,, bismuthinite. It is used mainly for 
making fusible alloy, drugs, and pigments; as the demand 
for it is limited and closely controlled production is small. 
It is usually of deep-seated formation, and occurs in quartz- 
veins associated with tin, tungsten, copper, gold, cobalt, 
and uranium. As both the sulphide and carbonate are 
relatively insoluble bismuth ores are not readily concentrated 
in the surface zone. Owing to its insolubility it occurs in 
alluvial deposits, and is obtained in Southern China from 
tungsten placers. Saxony once had almost a monoply, but 
its yield has become insignificant; the main supplies come 
from Queensland, where it is obtained as a bye-product 
from the tin and tungsten placers, and from Bolivia, where 
it is obtained from tin mines. The price generally varies 
from between 8s. 6d. to 12s. 6d. a lb.