The Norfolk Virginian. [volume] (Norfolk, Va.) 186?-189?, 1896-02-14
ABOUT PRECIOUS GEMS
Some StoRts Lose the Beautiful Color En-
tiTely Uider Heat and Sunshine.
GEMS THAT GLOW IN THE DARK,
Curious Effect of Age and Wear
Smoky Quartz Cristais-The Ruby
Will Stand More Kent Ti;nn the
b d-Phosphorescence I'm the
l Valuable Gems.

s (Copyright, 1896, by George +. Kunz.)
G An interesting topic is the alteration
& Of the colors of gems. either naturally
y or artificiaily. These changes are known
#only in few precious stones, but In
l&these. particularly in topaz, quartz and
turquoise. they are very marked. Crys-
kfals of true topaz are often found white
cor co7orless. and they are thought to
have been bleached by light or heat. as
1 this effect may be produced artificially.
1.-THE blue. brown and sherry-colorcd to-
ispazes are rendered colorless in short
sstime by sunshine. or even by strong
&daylisht; while the deep yellow variety.
5Swhen heated. changes TO pink: on fur
ether heating, to paler pink; and II the
HEAT be long continued, IL loses color
Henairely.
sssf These pink stones are known as rose
s{or pink topaz. The change is produced
SSby boiling in glycerine. or by burning
sin sponge
81 The brown transparent quartz known
Sas smoky quartz is affected in a some
what similar way. On heating the
gray-bIown, or hair brown becomes
3Ereddtsh-brown and reddish-yellow.
Most of the yellow quartz topazcs are
thus produced from the smoky variety.
There are various shades with different
names. such as Spanish topaz. Saxon
topaz. Scotch topaz, and CaIrngorm
stone. These have very rich tints of
deep yellow, red-gold and golden
Drown.
It is stated by Kleiner that the Rus
z5ian peasants In the province of Perm.
where these smoky quartz CRYSTALS are
largely found. are accustomed to alter
Ihem from brown to deep yellow by
baking them in loaf Of bread. If the
color Is not sufficiently changed. they
are baked three or four times dntil
sufficiently done). He also states tina;
they are apt to explode In the process,
This is probably due to the fact that
.fney often contain many minute cavi-
lies hlled with fluid. usually liquid car
,ponfc acid. which expands by the heat
WIN such force as to break the CRYSTALS
Heat. likewise, changes zircon from
deep red-brown to yellow and even
White, and also decolorizes the ereenish
varieties. In all such cases, this action
OF neat strongly suggests that the color
ing matter must be some carbon com
pound that Is decomposed at a high
temperature
$ Certain forms Of turquoise are unsta-
pie IN color and liable to turn green.
ne clear light blue of this stone is very
delicate; and wearers OF turquoise rings
are always cautioned to remove them
aWnen washing their hands, lest the color
sbe injured. Sometimes they turn green
kWNtout apparent = arse, and - is
sthought that acid emanations from tha
SKIN aH,ct them, and also certain 90
Fiosnes and other perfumes when tho
5aicohol eVaporates and leaves the essen.
$tial oils.
Many old fancies as to turoro;so
changing color in sympathy Win INC
ssickness or health of the wearer NAV
nave some foundation in facts Of .his
kind VI 'hiS
Is also subject 10 an a,tera-
stion, which consists in a deepenjnp of
the cosor with age. Some old ambcrs
are almost red; but this change is oniy,
superficial. and il the piece be re-c,it
the original golden-yellow is oftee,
found unchanged in the centre al
sIiineugh In great age It is changed
throughout.
fSose quartz is said to fade by exnos.
Ut 20 the sunlight, yet have gathered
sst lae9eaaAed pink masses in Oxford conn
~ Ae. The common Brazil nmetbys+
certainly, lose some OF its purnIe
n oelns worn on the hand due eitbar
action OF light. VI 10 me
Oh tN.,osure to strong sunlight waa Iono
eg{ltsS i"una 10 impart q reddish tint re
5; s; Fslay -colored agates; and this method
i i IL Deen used 10 convert them into car
ssnelians. In addition 10 this ,,a,.Io
~ seIn'cal means are employed 70 co,or
.sngates and chacedonies, and most =,
q ness ~ sh-calored specimens of these
:sssones nave been thus artificiallv