GO FIELD MUSEUM OF NATURAL HISTORY 
aluminum in such form and quantity that it may be profitably 
extracted. These include the present universal aluminum ore, 
beauxite, and some minerals from v^hich aluminum may be 
smelted in the near future. 
The adjoining case contains ores of tin. 
TIN. 
Tin ores from South Dakota, New South Wales, Mexico, 
and Alaska, together with a nearly complete collection of the 
ores and rocks of the well-known tin mines of Cornwall, which 
have been worked from the beginning of history, are shown. 
The process of reduction of tin ores to metal is illustrated 
by specimens from the Redruth Smelting Company of Cornwall. 
Other examples of tin ore may be seen in the West Dome. 
Following the tin ore is a case of nickel and cobalt ores. 
NICKEL AND COBALT. 
A series of specimens of nickel and cobalt-bearing minerals 
is arranged in the order of their richness. 
A collection of nickel and cobalt ores from the important 
deposits of these metals is shown. The most important ores 
are two: (1) the sulphide of iron, pyrrhotite, which, in some 
localities, carries minute inclusions of the sulphide of nickel, 
pentlandite ; (2) the apple-green silicate garnierite. 
Nickel and cobalt ores from Canada, New Caledonia, and 
Norway, also nickel and cobalt ores from Oregon, Missouri, and 
other minor localities, are shown. In the floor case opposite 
are larger examples of nickel ores. 
Following the nickel and cobalt ores is a case of manganese 
ores. 
MANGANESE. 
A collection of minerals carrying manganese in commer- 
cially available quantities, is shown, also ores of manganese 
from many important mining districts. Especially to be noted 
are the ores from Santiago de Cuba, which are typical, and 
those from New Jersey, which are unique in mineralogical char- 
acter. Polished specimens of rhodonite from England, illustrate 
an occurrence utilized both as manganese ore and for ornament. 
