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Helpful Information: Topaz is a gem of pastel shades and is
usually found in more intense colors only with the help of treatments such as
heat and irradiation. Almost 100% of the blue topaz on the market today is
heated and irradiated which produces a stable blue color. The colors range from
a pale blue called sky blue to progressive darker shades called baby Swiss blue,
American blue, Swiss blue, and London blue. Other topaz colors such as yellow
and pink can be enhanced through treatment to produce gems that show a pinkish
or reddish tint. The pinkish or reddish gems are called Imperial topaz; the
yellow are called Precious topaz. Since the crystal habit is orthorhombic, topaz
is usually cut in elongated oval or emerald cut shapes that maximize the yield
from this type of rough.
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| Brazil, Sri Lanka, Pakistan, Russia, Burma, Africa |
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| Al2(SiO4)(F,OH)2; Orthorhombic |
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Transparent
R.I. 1.61-1.63
Hardness 8 |
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| colorless topaz found in large sizes; precious
topaz rarely found in sizes above 10.0cts. Widely available except pink
and Imperial topaz colors. |
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| Colorless, Yellow, Red-brown, Light blue, Pinky
red, Pale green |
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| Irradiation and heat treatments bring out best
colors |
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| Avoid heat and strong light so colors won't fade
(blue color is stable). |
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| To distinguish topaz from citrine quartz, the trade
uses the term Precious topaz. Imperial topaz refers to sherry-red, deep
pink and reddish orange colors of topaz. Birthstone for November. |
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| Faceted in elongated oval or rectangular shapes due
to the crystal habit. |
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Blue in fine quality 10-36/ct
Precious in fine quality 135-270/ct
Imperial (pink) in fine quality 300-375/ct (2.0ct size)
$1125-$1350/ct (2.0-5.0ct. size) |
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