Vermont watchman and State journal. [volume] (Montpelier, Vt.) 1836-1883, 1856-03-07

muddy yellow or cloudy gray,
which, in their natural condition
would be yaueless, are passed oil as
stones OF the first quality. 1t is on
ly within the last forty years that
this process has been known in Ger
many but the Italian lapidarles
were acquainted with it centuries
ago. Hence we can account for the
exquisite color OF antique canoes
aud other ornaments once numerous
IN the cabinets Of Italy, and now to
be seen in museums and private col
lcclions all parts Of the world The
dealers, when making their purchases
of what we may call the raw materl-
al, select what appears to be de-
sirable piece, and chipping off mi
mute portion, they molslen the eX-
posed surface with the tongue, and
watch the absorption Of the moisture.
/ II regular aud equal, the stone is
good for an onyx if not 1t Is added
TO the heap OF inferior varieties
This, however, is but a rough and
ready test, and is not always deci-
sive.
The pores Of the stones, by which
the color is conveyed and retained,
are visible with the microscope and
the effect Of various tints is produc-
ed according as the hight falls upon
them at different angles. The rain
bow-agale is full OF minute cells,
which, when exposed TO The sun, pro-
duce prlsmatic colors as is observed
Of the slrin a molher-of-pearl 70
detect cavities 10 tie stones they are
soaked in water, which, slowly pc
uetraung, reveals the hollows. Some
already contain water when first
found and it is remarkable fact,
that if kept in dry place, the water
disappears, but without leaving the
slightest trace of moisture on the
surface and the stones can only be
re-hIled by boiling them.
Balls Of striped red chalcedony are
much priced large one, weighing
hundred pounds, was found ia
1s1l near WeisseIberg, aud was sold
10 the rough for 700 gulders Some
kinds Of chalcedony nre made to APP
pear Of cilron yellow, 10y a two
DAYS roasting M an oven, and a sub
sequent immersion in a close hot
bath of spirits of salt for two or
three weeks. A blue color which
has all the effect Of turquoise, is also
produced but the particular color
ing process has hitherto been kept a
secret. Those stones which are ma
trraly colored are at times roasted,
to helghlen the tint and add to its
pemanency. The Brazilian corne-
han becomes s.ngularly lusrous M
der the process the explanation be-
ing, that The long-conilnucd action OF
heat rcmnves the oxyhydrate OF iron
coutuincd in the stone, leaving II with
clear brightness difi'usrd 'h~~"Sh
the whole mass. The smallest stones
are roasted before polishing but the
large ones, OF which saucers, vases,
cups. plates, &c, are made, are first
cul into the required shape and thin
ness-oihcrwis they fly to pieces
when exposed TO heat After all the
coloriug operations have been gone
through with, the stones arc ground
on a wheel soaked IN oil for a day
to conceal the fine scratches and give
a good polish, and then cleaned of
with bran
Those who examined the collec-
ton OF gems and works Of art from
rare stones, IN the great exhibition
OF 1851, will remember the elegant
ONYX vases Of different colors-Some
: sreaked with white natural VEINS
the cups of red chalcedony a chan
/ of the same substance i'll large square
links of different colors, and with
out visible joints beside other OBJ
jecls So beautifully finished that {
prize medal was awarded to tn,
manufacturers.
, So far, we have been treating o
) methods by which art assists ma
; ture we come now 10 the gems
2 that are not found in the side Of {
quarry, but found in a chemist,
. laboratory. Before the days of Ber
= lin wool aad crochet work, young
, ladies' used To amuse themselves hy
} making crystalline baskets and trays
} as ornaments for the mantel-plece
but they had first to dissolve thei
J alum. The chemist works by 9th
er means and especially since the
= application of electro-galyanism Il
hls processes, there IS something
= really wonderful in the results. He
produces crystals at pleasure, aud il
humps that would atomsh those whC
, once labored so hard IN search o
the philosophers stone. A few
years ago, M. Ebelman laid be,
fore the French Academy Of Scien,
, ces specimens Of artificial quartz
, some white, others blue, red anC
, violet aud by mixing chloruret oi
gold with the siliclc acid used it
the composition, he produced =
, mass traversed throughout with de-
licate veins Of gold, similar to the
, Jumps brought from Australia and
California. BY a modification oI
, his process, he produced hydrophane
that species Of opal which is iran,
, sparent only when immersed il
= water and specimens also Of the
/ allied crystal hoalile. In this op.
eration. sllicic. ether and moist all