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| Gemstone
Buyer's Guide: Tanzanite |
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Tanzanite
Buyer's Guide
This remarkably popular gem was
discovered during the late 1960's in Tanzania’s Great Rift Valley.
A relative newcomer to the gem and jewelry scene, the last 30
years has seen tanzanite establish itself with great success
becoming America’s #1 selling gem after blue sapphire. Its meteoric
surge in popularity had taken the gem world by surprise.
Although actually a blue variety of zoisite, Henry Platt
of bespoke New York Jeweler, Tiffany & Co., coined more appealing name tanzanite,
after its country of origin. Its beauty and impressive value-for-money
underlie the secret to its success. Compared to ruby, sapphire and emerald,
the affordability of tanzanite gives consumers more sparkling gem for less
money – making it a competitor that has made sizable inroads to the markets
of other more traditional precious gems.
While arguably the easiest to assess of all the precious gems, understanding
where value lies in tanzanite still requires some basic knowledge of this
gem species. All the standard gem-value measurements are applied, but it
must be remembered that prevalent tendencies of this richly colored gem
for large sizes and high clarities do affect their pricing structure. |
| Color
Is The Most Important Factor In Determining A Tanzanite's Value |
Popularized
by beautifully rich purple-blue colors, tanzanite frequently
displays a deep intensity that is found nowhere else in the gemstone
kingdom. Attractive eye-catching red flashes of fire (a "trichroic" light
property unparalleled by other gems), often augments tanzanite's
spectacular color. As with most other colored gemstones, the
richer the color of the specimen, the more desirable it is.
Although traditionally thought of as an intensely purple-blue gemstone,
tanzanite also occurs in a variety of other colors such as pink, green,
ultramarine and a steely kind of blue. Frequently these tanzanites exhibit
a color change from the more bluish hues under daylight, to pinkish violets
under incandescent light.
How Carat Weight Of Tanzanite
Affects Per Carat Prices
Tanzanite frequently occurs in large crystal sizes and such specimens can
be thought of as being fairly accessible. These large sizes also help to
enhance tanzanite's perceived depth and richness of color.
Similar to most other gems, when the carat weight of a tanzanite increases,
so does the price per carat. However, large tanzanite crystals with their
abundant occurrence rates are simply more plentiful than ruby and sapphire.
This means that weight related price jumps in tanzanite are far less severe
than in ruby and sapphire. Indeed, it is not uncommon for comparable quality
3 Carat, 4 Carat, and 6 Carat tanzanites all to have the same or very similar
per carat prices - something that is unthinkable for ruby and sapphire.
Freedom
From Inclusions
Large, gem quality clean tanzanite crystals are relatively common when
compared to other precious gems. Well known for their predisposition for
virtually flawless clarities, this tendency enhances sparkle, brilliance
and ultimately beauty. While it would be incorrect to say tanzanite is
a clean gem species, with so many near flawless tanzanites available on
the market, obtaining such top quality clarities is within everyone's grasp
- something that cannot be said of ruby, sapphire or emerald.
Shape & Cut
Tanzanites are found in a variety of shapes and cutting styles. Ovals and
cushions are most frequently seen, but round, emerald and trilliant cuts
are also not uncommon. Like many other gems, slight premiums are levied
upon round tanzanites due to the higher loss of costly crystal rough during
cutting. Conversely, discounts are frequently given for pear and marquise
cuts.
A well-cut tanzanite is symmetrical and shows good polish; facets should
be aligned straight in relation to each other, and the girdle; polish conditions
should be mirror like with no visible flaws, pits or polishing lines.
Unlike ruby, sapphire and emerald, cabochons are infrequently seen in tanzanite.
This serves as a reminder of tanzanite's predisposition for high clarities.
Sources
Of Tanzanite
The world's most predominant source of tanzanite is the Merelani deposit
in Tanzania, East Africa. Located in the Rift Valley close by to Mount
Kilimanjiro, the mines barely cover 20 square kilometers. With such limited
deposits, it is likely that tanzanite can only become more valuable in
the future.
Out of the individual deposits at Merelani, a subsection
known as "D
Block " has earned the reputation and kudos for producing the very
best "AAA" quality tanzanites. While characterized by intensely
deep purple colors with glistening flashes of red, tanzanite from the other
locales such as "C Block", can be in reality produce gems as
every bit as fine.
The Use Of Heat
Virtually all tanzanite is heated to about 500°C in order convert its unsightly
brownish coloration to a more appealing blue. Most tanzanites seen on the
market today have been subjected to heat treatment, an age-old practice
thought to have originated in Sri Lanka some 2,000 years ago. Without this
practice, virtually no tanzanite at all would be seen on the market today. |
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