88 J. L, Smith on the Emery mine of Chester, Mass. 
All the chemical and physical examinations made go to show 
that the emery of Chester is, like all other emeries, a mixture of 
corundum and nts - iron; a@ fact that will be reverted to 
again a little farther 
Prof. Jackson amaizied two specimens, after digesting them 
with nitro-muriatic acid, and has given as the composition, 
x 2 
Alu - - - 60°40 39°05 
seine ah iron, - - - 39°60 40°95 
and a goes on to state, ‘from which it would appear that 
proto of iron is an essential chemical ingredient in emery, 
and not an accidental admixture.” Dr. J. Lawrence Smith’s ex- 
po lead to the same result, but he considers the oxyd of 
n to be an irregular mixture with the alumina and not a reg- 
ula chemical constituent. In either case, I think emery ought 
to rank as a separate species, and not as a granular variety of 
po ea from which it differs so in physical characters.” 
Iw ould here remark that Dr. Jackson's conclusion would be 
correct in the first state of the case, were the iron an essential 
chemical Fionn: but in the latter, it would be erroneous, and 
introduce inextricable confusion into the science of mineralogy 
by 89K 4 mere mechanical mixture as a specific distinction. 
Prof. C. U. Shepard writing on the same point says, ‘ His con- 
clusions (Dr. Jackson’s) would obviously be acquiesced in were 
it not for the strong resemblance in striz and cleavage between 
the emery and common corundum, making it impossible for us 
to separate the substances erystallographically from one another. 
othing like a hare crystal of emery has yet been found at 
the mine; but it is quite remarkable that the mineral is here 
generally’ coarsely massive, or in large separate individuals often 
of the size of kernels of Indian corn, whose cleavages are per- 
and which present on their planes the delicate strize so char- 
tie Cer of corundum from the Carnatic.’”’ Yet Prof. Shepard 
or making emery a new mineral species and calling it Hmerite, 
with the formula FeAl 
If the views of Profs. Jackson and Shepard are to be taken as 
correct, the question as to the mineralogical —_— of — is 
easily settled without resorting to any new mineral s It 
is simply a massive iron-spinel (hereynite) oriths the one of 
having a hardness equal to corundum. 
Emeries, 
: ‘Tron spinel. Jackson. Shepard. 
Alumina, - - 58-75 60°49 xP 
Protoxyd iron, - 41°25 39°60 : 
I would say, at this point, that if the mineral of Chester is to 
ts — as an aluminate of iron, the rock called emery 
examination of my analyses in 1850, which it is su py are the ones re 
tie to here, most certainly do not sustain the conclusion. : J. Le 
