is the name for the mineral species that is number 8 on Mohs’ scale
of hardness. There is some uncertainty
regarding the name. Some say it comes from the Sanskrit word meaning “fire.” Others
link it to the Red Sea Island of Topazios
(Zabargad or St. John’s Island), where peridot has been found.
Egyptians thought the stone was colored by the mighty sun god Ra
and was worn as an amulet against harm. During the Middle
Ages, engraved topaz was used by clergy and royalty to promote goodwill.
is the official gemstone of Texas and Utah and blue topaz is the
gemstone of the 4th anniversary of marriage.
the general public, topaz means a yellow gem,
and much citrine and smoky quartz has been sold
as “golden topaz” and “smoky
topaz.” The terms “imperial” and “precious” topaz
are often used to distinguish between true topaz
and the quartz look-alikes.
name “imperial topaz” is said to
have originated in the 19th century in Russia,
where the Ural Mountain mines were an important
source. According to some sources, pink topaz
from those mines was restricted to the family
of the Czar. Today, the gem trade generally uses
the term for pink, orange and red topaz, which
comes mainly from Ouro Prêto, Brazil. Fine
pink topaz also comes from the Katlang area of
|Three different flavors of imperial topaz
from Brazil. 4.8 cm. high. The most highly sought would be
the pink gem at right. Gems: Pala International; Photo: Robert
commonly occurs in colorless and brown colors, it is the rare golden,
orange, pink, red and purple colors, which are often termed “precious” or “imperial” topaz,
that are the mainstay of the fine gem market. While blue topaz is
found in nature, most of the material is produced by a combination
and brown topaz owe their color to color centers.
The impurity chromium produces pink to red colors.
A combination of color centers and chromium produces
orange topaz. Blue topaz is colored by color
that the color of some brown topaz may fade with
to its orange to red-orange color, topaz generally looks best under
incandescent light. In contrast, blue topaz looks best under daylight
or fluorescent light. When buying any gem, it is always a good idea
to examine it under a variety of light sources, to eliminate future
|A gorgeous brown topaz crystals from the
Mogok region of Burma. 4.8 cm. high. Crystal: Carl Larson collection;
Photo: Jeff Scovil
from most sources is reasonably clean. Thus eye-clean stones are both
desirable and possible. The exception is with pink and red topaz, where
only small stones are normally available. In those colors, a slightly
higher degree of inclusions are tolerated.
to the shape of the rough (elongated prisms), topaz is generally cut
as elongated stones, typically emerald cuts, elongated ovals, cushions
and pears. To save weight, pears in particular are often cut with overly
narrow shoulders. Due to the huge production, blue topaz is cut in
virtually any shape and style one can imagine. Cabochon-cut topazes
are rarely seen.
topaz does have a perfect basal cleavage, it is
not an easy cleavage, and so does not present too
much difficulty to the cutter. Nevertheless, cutters
will often try to ensure that no facet is parallel
to the cleavage direction and jewelers try to mount
valuable stones in settings that protect the stone.
|Magnificent intergrown brown topaz crystals
from the Mogok region of Burma. 8.5 cm. high. Crystal: William Larson
collection; Photo: Jeff Scovil
prices of topaz are, like any gem, dependent on quality. Still, a
few generalizations can be made. Blue topaz, the most common variety
seen in jewelry today, has been produced in such quantities that
today it is generally available for $25/ct. at retail for ring sizes.
Larger sizes may be slightly more. While natural blue topazes are
known, the huge production of treated blue topaz has essentially
dropped the price of the natural blue down to that of the treated
topaz, from which blue topaz is produced (via
irradiation and heat), is available in sizes
up to 100 cts. and greater, and sells for less
than $8/ct. Brown topaz fetches similar prices.
contrast, precious topaz (a.k.a. ‘imperial’ topaz)
in rich orange colors fetches prices
in excess of $1000/ct. for large (10 ct.
+) sizes. The most valuable topaz is
a rich pink or red color, and can reach
$3500/ct. at retail. These are rare
in sizes above 5 cts.
Topaz sometimes occurs in enormous sizes, where
clean gems of even 1000 cts. are known. Indeed, faceted
stones of tens of thousands of carats have been produced from
some monster crystals. However, cut stones of the prized “imperial” colors
(orange, pink and red) are more rare. Fine pinks and reds above
5 cts. are scarce. Fine oranges above 20 cts. are also
|Three different examples of treated blue
topaz. Gems: Pala International. Photo: Wimon
topaz has been found at a number of localities around the world, including
Brazil, Nigeria, Sri Lanka, Russia, Burma, Pakistan, USA and Mexico.
The premier source is near Ouro Prêto in
Brazil’s Minas Gerais state.
previously mentioned, several varieties of topaz are typically enhanced.
Most common is the combination irradiation/heat treatment that produces
blue topaz. For this treatment, colorless topaz is irradiated, turning
it brown. The stone is then heat treated, which turns it blue. While
the brown color is generally unstable, fading with prolonged exposure
to sunlight, the blue color is generally stable under normal wearing
are three main flavors. The first, a “sky” blue,
is produced by gamma rays (cobalt 60). Deeper “Swiss
(a.k.a. ‘windex’) ” and “London” blues
are produced by high-energy electrons (cyclotron)
or nuclear radiation. In the latter case, the
stones must be allowed to cool down to safe levels
of radioactivity before being sold. This typically
takes a few months to as much as two years.
treatment seen on occasion with topaz is bulk
diffusion, where stones are heated for long periods
surrounded by cobalt. This drives the cobalt
into a thin layer at the surface, turning it
green to blue. The layer is extremely thin.
some topaz is coated with metallic oxides, similar
to the coatings on camera lenses. This produces
various colors and rainbow-like reflections,
but the coatings are easily scratched. The material
has been marketed under the name “rainbow” topaz.
has never been synthesized, but a number of imitations exist, including
natural stones such as citrine and smoky quartz, and man-made imitations
such as glass.
has the following composition:Al2(F,OH)2SiO4
(but not that easy) basal cleavage
||3.53 ± 0.04
usually occurs as vertically striated elongated prisms topped
Orange, yellow, brown, blue, pink, colorless,
to moderate, dichroic
safe; never clean topaz ultrasonically
Steamer: not safe
The best way to care for topaz is to clean it with warm, soapy water.
Avoid exposure to heat, acids and rapid temperature changes. Strong
heat may alter or destroy color
Most blue topaz is made by irradiation and then heat; this treatment
is undetectable and extremely common
Blue topaz irradiated with in nuclear reactors can emit dangerous
levels of radiation; it must be allowed to cool down to safe levels
Some orangy topaz is heated to destroy the color centers, leaving
behind the chromium-caused pink color
The Collector Gem Buying Guides
In addition to the above, please visit the Learning
Vault at Palagems.com for many additional articles on gems, minerals and mining.