Daily Kennebec journal. [microfilm reel] (Augusta, Me.) 1870-1975, 1913-09-08

ployed as the eoIoring agent This' now
ever does not readily form an ai',i,'''''
in the same way that II does
and. in consequence, it is lhlPo9a'pie "
produce a satisfactory coloralioh III '''e
corundum by its means; it is poSsio'. "
get the cobalt i'm a state of cothoi'i'''o
by adding large proportion OF MAG ieSii
to the alumina, but then the pt'"'e
formed is not Il crystalline alumlhh' pu'
magnesium illuminate and its proper t'es
are fundamentally different. lis Ieii az
tive index is lower, in fact the result 10
blue spinel instead of sapphire -"''
over, such blue stones have me ''''' ~
teristic absorption of cobalt ana appear
purple in a light that does not eo"''''i
large proportion of blue rays
In 1903 Paris attempted 10 aNold this
latter difficulty by preparing n ealeiuti
illuminate colored with cobalt as /, is
found that in this ease the TRANSMISSION
of the red rays is less pronounced. but
the calcium illuminate So formed IS not
crystalline at all, but amorpho0s. a year
or so ago, however, the problem OF pro-
ducing synthetic sapphire was IhialiS
solved by the use of titanium oxide,
very unexpected result, CONSTRUCTING
the chemical position of this clement.
With this last advance the arfihclal pro-
duction of the eorundum gem stone may
be considered To be completely solNea,
and cut stones can now be obtained III
every vafty of color, from pure "tlte
to ruby aud sapphire. ut prices ranging
from four to 10 shillinss a carat accord
ing to color quality and size.
AS regards the remaining Transparent
gem stones, which fail into a group by
reason of the fact that they contain
silica as an essential composition, Their
artificial product is of little importance.
They cannot be produced by the same
process as corundum. owing to the fact
already alluded 10, that under such con-
ditions both pure silica and compound
silieates yield an amofphoas product.
which has not the optical properties OF
the natural stone. one is constrained
for the artificial production of the erys-
talline material, To IA back upon meth
DDS similar To those employed IN the
early attempts 10 obtain ruby-obtainlns
requisite composition by chemical re-
action. and maintain the mass at tenn
perature much above its fusion point for
a sufficient time to allow the siieate to
crystalline out.
Topaz. garnets and Zircon have been
produced in this way SUPPLEMENTARY as a
matter of scientific interest, for the
small stones produced have no CONNER
cial value, and to describe their produe-
ton In detail would only weary You te
no purpose. The majority of these stones
are of such common occurrence in ma
ture, and consequently of such little
value, that their artificial production II
this manner is not commercial propo'
sition.
An exception. however. must be made
in the case of emerald, which ranks nexi
i'm value To cerundam. and many at
tificially. RECONSTRUCTED emeralds have
been made by the Nerneull process, but
these are, of course. amorphous, and do
not possess the double refracton ans
other properties consequent upon crys
tolline structure of the natural stone
the problem of producing this stone ar
tificiallv has not as yet been solved II
fact. l am quite aware i'm saying Thu
that recent newspaper reports lead on,
TO believe otherwise, but. as in the cas-,
of the diamond. such reports indicate
either remarkable foresight on the par
of the writer's or show that their imagi.
nation is developed at the expense OF
their powers of accurate observation =
New York Times.