360 J. Eewrence Smith on Emery. 
Enough having been said to prove that the. emery under con- 
sideration was formed within the limestone. in which it is found, 
I will allude to process of segregation which has given rise 
to this formatio 
It would. sane that the substances. pfininated fines the calea- 
reous rani were silica, alumina, and oxyd of iron, and that these 
three in the exercise of homogeneous - and chemical attractions 
have given rise to the minerals which consti itute an are assocla- 
isa j 
ted with emery. In my collection, there is 
ing this. fact in a remarkable manner. dt is a 
emery in the center, with two concentric. yer the inner of 
chloritoid and pa outer of emerylite ; the. tter was in nh contact 
with the limest 
Em ery ~inixtie of corundum (lumina ale bydrated) and 
oxyd of ir 
Chlorioit—sle 24, alumina AO, oxyd of, iron 28,, water Io 
- Eme 30, 0, lime 13, water 
Ati in ae caine in commencing from the external. cop . 
thick direction we must regard the consolidation of the:no 
that the larger portion of silica eliminated as combined witl “a 
Jargé portion of alumina and some lime to tome a pecuhar mine 
t, the remainder of the silica ‘combines. with an aditional 
hex 
quantity of alumina and considerable oxyd of iron to form another 
‘mineral ; and finally the remaining alumina and oxyd of iron 
crystallize separately.. Facts of this kind in geology are not un- 
frequent, but they are always highly a and worthy of 
remark. 
In coneluding the geological considerationsof emery with ref- 
erence to the localities in Asia Minor and the. mh islands, 
I would remark, that at some Jour time when the observations 
become extended, it will doubtless. be found that the emery forms 
the geognostic mark of extensive calcareous,formations in that 
part of the world, just as the flints do in the chalk of Europe. 
Mineralogical position of E'mery. 
Emery has been considered by some as corundum, others sup- 
it represente some rock or other, not always the same, 
in which corundum is disseminated in greater or less quantity ; 
others again consider it a mixture of corundum and oxyd of iron. 
I am of opinion that the latter is the most correct manner of re- 
garding this substance. 
Emery properly speaking is not a simple mineral, but a me- 
chanical mixture of granular corundum and oxyd of iron in which 
the former usually predominates. It has not the aspect of corun~ 
dum disseminated in a rock, for it is found in ns — of 
different dimensions and of great hardness; and when broket 
giving way in the directions Sf fissures, which oxy co 
