pratt,] EMERY. 67 
County, a variety has been found that may upon development prove 
to occur in commercial quantity. While no tests have been made to 
determine the abrasive quality of this corundum, preliminary fire 
tests have been made which indicate that it is suitable for use in the 
manufacture of the vitrified wheel. Then, again, the percentage of 
corundum in the ore, simply judging from the hand specimens, is 
high enough to make this a workable ore if in sufficient quantity. A 
description of the rocks in which the corundum occurs is given on 
page 30. 
EMERY. 
Until recently the only emery known to occur in the United States 
was that at Chester, Mass., and Peekskill, N. Y., the principal mining 
being done at the latter place. Emery lias now been found in North 
Carolina in a very promising prospect. As is staled on page 9, emery 
is a mechanical mixture of corundum and magnetite, or sometimes 
hematite. From Ms striking resemblance to iron ore, especially where 
it is a mixture of corundum and magnetite and is therefore magnetic, 
both the deposits at Chester and Peekskill were first worked as iron 
ores, and it was not for some time that their real nature and value 
were understood. Since then the deposit at Chester has been worked 
continuously and extensively. 
Spinel is sometimes associated with the emery and increases in 
amount until it is largely in excess of the corundum, and the ore 
passes over into what might well he called a vt spinel emery." 
MASSACHUSETTS. 
The only deposit of emery that has been found in this State is 
in the vicinity of Chester, where the emery vein has been traced for 
nearly 5 miles. The vein is first encountered about 2 miles north- 
west of the village of Chester, in a ledge that projects into West- 
field Rive]' from its left bank. The vein can be followed almost 
continuously along the line of the strike — south to a little east of 
south. It extends across the east slope of Gobble (North) Mountain, 
drops down into and crosses the narrow valley of Walker Brook, and 
then rising, it crosses South Mountain and can be followed for over 
2 miles to the south. The map (fig. 13) shows the general position of 
this emery vein, the places that have been opened along it, and the 
location of the different emery mills. The emery occurs in an amphibo- 
lite, which has been described on page 23. 
Beginning at the southern end of the vein the first work has been 
done about half a mile north of where the vein disappears, at what is 
known as the Wright mine. About twenty years ago rather exten- 
sive mining was being carried on here, the work consisting of an open 
cut nearly 1,400 feet long that was worked to a depth of 6 feet at its 
southern end and about 30 feet at its northern, with probably an 
