26 CORUNDUM, ITS OCCURRENCE AND DISTRIBUTION. 
EMERY. 
Emery is the intimate mechanical admixture of corundmn and either 
magnetite or hematite. Its vahie as an abrasive is dependent ii])on the 
percentage of corundnm, for it is to the presence of this mineral 
that the emery owes its abrading qualities. This mechanical admix- 
ture of corundum and either hematite or magnetite is usually so inti- 
mate that no separation of the two on a commercial basis can be 
made, and emery can therefore not be used as a source of corundum. 
When very finely crushed, the iron oxide can be separated from the 
emery by means of an ordinary electromagnet. Examined under 
the microscope, the two minerals can be seen distinctly. Sometimes 
the corundum is in coarse grains or distinct crystals. At Chester, 
Mass., emery has been found containing crystals of corundum nearly 
half an inch in diameter. 
In appearance emery is very similar to fine-grained iron ore, and 
when it contains the iron oxide, magnetite (FcgO^), it is almost 
identical in appearance with that ore itself. Its color is blue-black 
to black, and it has a metallic luster. When emery was first dis- 
covered, it was mistaken for an iron ore, and a number of cases might 
l)e cited where attempts have been made to work deposits of emery 
for iron ores. At the largest American deposit, which is located at 
Chester, Mass., it was first thought to be a magnetic iron ore, and blast 
furnaces were erected and the mine was operated as such. At the 
first attempt, how^ever, to smelt the ore in the furnaces they became 
clogged up, and the mine was condemned as containing a very refrac- 
tory ore. The mine remained idle for a number of years. Dr. H. Sv 
Lucas then bought it and began to operate it as a source of emery. 
This mine, which is now oAvned and operated by the Ashland Emery 
and Corundum Company, and the mines at AVestchester, N. Y., pro- 
duce all of the emery that is mined in this country. 
Spinel sometimes is associated with emery. At times the spinel is 
largely in excess of the corundum, and the mineral then might well 
be called a '' spinel emery.'' This is well illustrated at the West- 
chester mines, in New York State, and in some of the emeries from the 
Grecian islands. 
Emery is sold on the market under the head of Turkish, Naxos, 
Chester, and Peekskill emery, according to the locality from which it 
is obtained. It was first obtained from the Grecian islands, the prin- 
cipal one of which is Naxos, upon Avhich there have been seventeen 
deposits of emery located. This locality controlled the emery market 
until the important explorations of Mr. J. Lawrence Smith developed 
the large deposits in Asia Minor. By these discoveries a new source of 
emery was opened, which at once reduced the price. The best Turkish 
emery is thought to be that which is found in the Abbot ndne, and it 
