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Pink Topaz
As already mentioned, true or yellow topaz may
be pinkish orange or yellow with a pink tinge. There is in
fact a whole range of color gradations from yellow to pink,
and it is hard to establish a dividing line between the two
varieties.
Appearance In some cases the
color is pink with a distinctive yellowish or orange shade,
but it is more often a definite light to medium pink, tending
to red or violet in deeper colored stones. The color is not
always evenly distributed and can show slight crystallographic
zoning. The stones usually have few inclusions and are strongly
transparent and lustrous.
The most common cut is the oval or pear shape,
but many other old or antique faceted cuts are seen, as is
the step cut. While it has always been comparatively rare,
pink topaz was much appreciated in antique jewelry and stones
weighing up to 10 carats are often found.
Distinctive features At first
sight, there is not a lot of difference between pink topaz,
kunzite, morganite, and some pink tourmalines. But a density
test with a heavy liquid such as methylene iodide, in which
topaz sinks but the others float, will distinguish topaz from
the others. It is harder to tell pink topaz apart from pink
spinel and pink corundum, the former having about the same
density as topaz, and the latter having a higher density.
In case of confusion with these stones, other properties,
such as the refractive indices, need to be examined.
Occurrence Pink topaz comes
mainly from Brazil, but has also been mined recently in the
Ural mountains of the Soviet Union. In both places, intensely
colored reddish or purplish specimens have very occasionally
been found.
Value When the color is fairly
intense, it is one of the most valuable of the second level
of gemstones (e.g. aquamarine). Specimens that are too pale
have a low value. Like yellow topaz, it was perhaps more highly
prized in the pas' than today.
Simulants and synthetics At
one time glass imitations were occasionally produced. In antique
jewelry, very pale stones were sometimes given a closed setting
with a painted base to heighten their color.
The pink color of many topazes is due to heat treatment of
pinkish-yellow stones from Brazil. This method goes back at
least several centuries, so even antique stones may have been
colored in this way. This procedure, however, has always been
regarded as admissible in the gem trade, so the question of
whether the color of pink topaz is natural or due to heat
treatment does not arise.
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