|
EMERY.
|
211
|
||
|
|
|||
|
Oriental
emery is nothing but granular corundum, that is, an aluminate whose
specific gravity is 4, and which, when analysed, yields
|
|||
|
|
|||
|
|
|||
|
|
|||
|
By some it is called adamantine spar, and
is found in China, Bengal, and Ceylon in large octahedrons, which,
under a given angle of luminous rays, reflect bluish light, but are
generally opaque.
The
best comes from China, and contains more oxidized iron than that from
Bengal. When pulverised, it scratches some gems, but not the diamond.
The
Western granular corundum, or Western emery, is rarely found in
crystals; it is more frequently disseminated in grains, like sand.
Although
excessively hard, it is less so than the Oriental. Its colour is black
grey, reddish grey, or bluish grey. It is seldom transparent, yet some
of its very fine particles shine brightly.
The
Western emery, which must not be confounded with the granite, magnetic
iron, and the compact red hematite, is found in Italy, Germany, and
Spain, at Smyrna, in the island of Nasso, at Jersey and Guernsey. That
kind which is found in Saxony lies between the strata of mica and
steatite. It is united with a great quantity of iron, from which cause
it is often attracted by the magnetic needle.
|
|||
|
|
|||