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Tanzanite
"Tanzanite is the most important gemstone
discovery in over 2,000 years".
Henry B. Platt, Former President & Chairman,
Tiffany & Co.
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The Masai, a
people forever linked to one of East
Africa's most spectacular gems,
Tanzanite
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A big claim from the bloke who introduced it to
the market, but with just over 40 years under
its belt, Tanzanite is a gem people still rave
about. The quintessential 'haute fashion'
gemstone of the 20th century, Tanzanite is one
of the best selling coloured gemstones of all
time. In recognition of the enormous popularity
it garners, Tanzanite joined Turquoise and
Zircon as the official industry birthstones for
December in 2002. As a December baby who has
visited the world's only source of Tanzanite,
this was also personally significant. Undeniably
drop-dead gorgeous, glamorous, exotic and rare,
the question still remains, why is Tanzanite so
coveted? Colour baby, colour. Tanzanite displays
some of the best 'velvety blues' in the gem
kingdom and, depending on your perspective, can
even give the finest Blue Sapphire a run for its
money! But more on its colour complexity and
comparisons in a moment, let's travel to where
our story begins, beneath the shadows of
Tanzania's Mount Kilimanjaro in the arid
Merelani foothills that rise from the hot Sanya
plains...
Five hundred and eighty-five million years ago,
something so geologically unique happened
beneath the earth's surface that some prophesise
only a one-in-a-million chance of Tanzanite
occurring elsewhere. Tanzanite's colours are
down to the amount and ratio of chromium and
vanadium, and it's the chance incorporation of
these elements into pockets of transparent
Zoisite (Tanzanite's mineralogical name) that
has resulted in one of the world's most
sought-after gemstones. Given that Tanzanite's
sole deposit scarcely covers 20 square
kilometres, it's no surprise that it is
routinely described as "a thousand times rarer
than Diamonds". Much like Zultanite, which also
only comes from a sole deposit, Tanzanite is as
much defined by its rarity as its beauty. Now
the cynics out there will probably doubt the "a
little over a decade of mine life remaining"
claims, but do try to remember that prophesising
the life of a gemstone deposit is a lot more
complicated than scheduling a train timetable,
and we all know how wrong they can be! Even
though the odd included Blue Zoisite crystal has
been found in Pakistan, Tanzania has the world's
only commercial deposit. The deposit has been
segmented by the Tanzanian government into four
'blocks' (A, B, C and D) and while production in
at least one block has increased, overall
Tanzanite production is decreasing. Unless
discovered elsewhere, newly mined Tanzanite will
largely disappear in years to come, probably
within my lifetime.
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AAA Tanzanite
& Diamond 18K White Gold Ring |
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According to popular myth, the first Tanzanite
aficionados were nomadic Masai herdsmen.
Apparently, they spotted beautiful blue
Tanzanite crystals which had been transformed
from their typical bronzy greyish brown by a
grass fire. While this romantic story alludes to
how Tanzanite's colours blossom with a little
gentle heating, it seems unlikely that a grass
fire could hit the temperatures needed (around
520°C). Perhaps this may have happened over time
under the hot African sun, but again, this
hypothesis reads more like urban legend
(virtually all Tanzanite is heated to
permanently enhance its colour,
click here for
more). Whatever the truth, the Masai are a
people forever linked to Tanzanite and by sheer
coincidence, the Masai regard blue as a sacred
spiritual colour. Once bestowing blue beads and
robes to women who have born children, the Masai
have now adapted this old tradition. Today,
Masai chiefs give Tanzanite to wives on the
birth of a baby as a blessing for a healthy,
positive and successful life.
Myths aside, in 1967 a 'man' discovered some
sparkling Tanzanite crystals and as they say,
the rest is history. The problem is, which
'man'? Variously attributed to Ali Juuyawatu,
Ndugu Jumanne Ngoma and others, visit any pub in
Arusha, located 25 kilometres north of the
Tanzanite deposit, and you're bound to be told
one version of the story. However, three things
are for certain: Manuel D'Souza staked the first
claim; legendary Scottish geologist Campbell
Bridges (the discoverer of Tsavorite,
click here
for more) was the first person to bring
Tanzanite to the GIA (Gemmological Institute of
America) for identification; and Tiffany & Co.,
specifically Henry B.
Platt, great grandson of
Louis Comfort Tiffany, coined 'Tanzanite' and
launched it to a willing world. While
Czechoslovakian Baron Zois von Edelstein, for
whom 'Zoisite' is named, was cheated out of
better recognition, I think we all agree that
'Blue Zoisite', which for Henry echoed 'blue
suicide', just doesn't fit. Christened Tanzanite
in tribute to the land of its birth, it quickly
became one of the world's most popular
gemstones.
But what good is a clever name if you can't back
it up with beauty? As mentioned previously,
Tanzanite is all about colour, so it will come
as no surprise that its grading systems mostly
critique colour quality. Tanzanite is pleochroic
(click here for more) or getting more
technical, trichroic (three-coloured). This
means each Tanzanite crystal has three colours,
blue, purplish-red and greenish-yellow brown
(bronze), whose intensity changes when it is
viewed from different angles. While heating minimises Tanzanite's bronze hues, maximising
the blues, violets and purples, this is
dependant on the natural characteristics of each
crystal and doesn't produce consistent results.
While Tanzanite's rarest and most valuable
colour is typically a strong daylight
'sapphire-esque' blue, most of the time,
Tanzanite's final colour is a combination of its
three trichroic hues, depending on the
prominence of pleochrosim in each finished gem. This is because Tanzanite with more blue than
purple or violet is faceted along the width, not
length, of the crystal to accentuate the purity
of the blue colour. This is an inherently more
expensive proposition because weight and size is
sacrificed for colour. While Tanzanite's colours
are typically blues, bluish-purples,
bluish-violets, purples, violets, violetish-blues
and combinations thereof, highly collectable greens, pinks and yellows are also known to exist. Tanzanite exhibits a colour shift (a colour
change where the two coloursare near each other
on the colour wheel) from its blues in daylight,
to purples and violets in incandescent lighting
(candlelight). This is a desirable trait, and as
most of us live in mixed lighting environments,
you can often see these colours simultaneously.
While industry paradigms dictate that Tanzanite
with a pure 'closest-to-sapphire' blue equals a
higher value, Tanzanite should never be viewed
merely as a Sapphire substitute. Even its finest
pure blues will display some violets and purples
in incandescent light, so while it's tempting to
make comparisons, Tanzanite's uniquely beautiful
colours should be appreciated for what they are
rather than what some would like them to be. Once you've accepted Tanzanite is hardly ever
pure blue, selecting a pastel or more intensely coloured Tanzanite is simply down to your taste
and budget. Just remember that colour and size
in Tanzanite are irreparably linked, so you're
generally not going find its richer, more
intense purple-blues in smaller sizes. While
gemmological beauty is in the eye of the
beholder, Tanzanite with excessive pleochroism
or a vivid purple or violet in daylight will be
priced accordingly. Also, be aware that
Tanzanite's deeper more expensive colours are
often identified by quality prefixes such as
'AAA'.
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AAA Tanzanite
& Diamond 18K Yellow Gold Ring |
Available in an array of shapes and sizes,
Tanzanite under 20 carats is most popular and
practical for jewellery. Ovals and cushions are
the most common cuts, but Tanzanite is also
available in rounds as well as other shapes.
While you should look for a shape, overall
appearance and deft finish that afford good
brilliance, the quality of faceting is important
for Tanzanite as the visibility of its
pleochroism is largely determined by the
lapidary techniques used to finish the gemstone.
Also, be aware that Tanzanite which is too large
or poorly cut will darken, losing brilliance.
Last but certainly not least, the clarity
standard for Tanzanite is usually eye-clean (no
visible inclusions when the gem is examined
approximately six inches from the naked eye) and
it can even display a good clarity under
magnification. This is important, as a high
transparency and an absence of inclusions
accentuates its glamorous colours, and are thus
signature characteristics of Tanzanite.
Despite a fleeting resemblance between Tanzanite
and fine Blue Sapphire, touting Tanzanite as
"looking like Sapphire wishes it could look" or
"sending Sapphire into a jealous rage"
ultimately seems awkward and perhaps a little
silly to me. In these competitions, no gem wins. The reality is that Tanzanite is not a Sapphire
substitute. As attested by its unabated
popularity and enormous public recognition,
Tanzanite is definitely its own gem. Despite the
intrinsic scarcity associated with a sole
deposit, Tanzanite is one of the most beautiful
transparent blue gemstones around. When you
compare its beauty to bucks, Tanzanite remains
exceptional value for money. |
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