OCCURRENCE AM) DISTRIBUTION OF CORUNDUM IN 
THK UNITED STATES. 
By Joseph Hyde Pratt. 
INTRODUCTION. 
Tn obtaining data for 1 liis paper many corundum localities were 
visited, especially those thai were thought to carry the mineral in 
commercial quantity. Although all the occurrences of corundum can 
not be described in detail, they are all mentioned in the tabulated list 
of localities, page 7'.). 
Considerable activity in corundum mining has sprung up within 
the last few years, and several aew occurrences of corundum in quan- 
tity have been brought to light, those of special aote being in Ontario, 
Canada, where the corundum occurs in a syenite, and in North Caro- 
lina and Georgia, where it occurs in a gneiss or a quartz-schist. 
The corundum Localities in the United States are, with the excep- 
tion of those in Montana, Colorado, and California, limited to the 
Appalachian region, the mineral having been found at various points 
throughout nearly its entire length. The mining of corundum has 
been, however, confined to a narrow section of the southern portion 
of that region, i. e., to northeastern Georgia and southwestern North 
Carolina, with the exception of the emery mines at Chester, Mass. 
Often a distinction is made between emery and corundum, many 
persons not recognizing emery as a variety of corundum. There are 
three names in constant use to designate the varieties of corundum: 
(1) Sapphire, which includes all corundums, of whatever color, that 
are transparent to semitransparent; (2) corundum, including the 
translucent to opaque varieties of all colors; (3) emery, which is a 
mechanical admixture of corundum and magnetite or hematite. The 
last two varieties are those used in the arts for abrasive purposes, 
emery being used in very much larger quantities than corundum. 
It is of course the presence of corundum in the emery that gives to 
it its abrasive qualities and makes it of commercial value, and the 
abrasive efficiency of emeries varies according to the percentage of 
corundum they contain. 
Any eorundtfm that is transparent is included under the head of 
sapphires, although many of these have distinct names in the gem 
trade. The blue sapphire is known as the oriental sapphire, the red 
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