Located in the northern part of
Tanzania, in the Usumburu Mountains inhabited by the farming and
herding Masai people of Africa, in an area called Merelani we get one
of the world's most exquisite gem forms of Zoisite. Zoisite was so
named after the Czechoslavakian Baron Zois von Edelstein who first
discovered it. But his discovered variety was a lifeless grayish white
and yellowish brown which had very little importance, prominence and
demand as a gem material in his homeland's region. It was not until
1966 in a far away continent in a very arid region of Africa that one
of the most recent and sensational gems the world has seen was
discovered by an Arusha tailor named Sousa. Of exceptional beauty in
its dark blue, violet-purple colorization, it was first believed to be
a rich colored sapphire material, until researched with proper
sophisticated gem identification equipment and found to be a completely
new gemstone form of Zoisite, never seen before. One year later
Tiffany's & Co. created a huge sensation with their advertised
announcement of the new gem, calling it from its country of origin,
"Tanzanite."
The Merelani Mine is located
south of the famous landmark, Mount Kilimanjaro and north of the
Olduvai Gorge where the famous paleoanthropologist Louis Leakey made
his famous early man discovery. The nearest town, Arusha, is over 50
kilometers to the northwest. It is a desolate region where in 1997 a
sudden deluge of over 7 inches of rain flooded the mine and killed over
thirty miners. It took almost a year to pump, dig and dry out the mine
plus claim the bodies, during which time a tremendous increase in the
prices of gem tanzanite was noticed on the world markets because of the
lack of material available. Most crystals, although heat treated for
increased color uniformity and saturation of hue, are not found in the
natural colors of deep violet-purplish blue but in the more common
colors of gray, brown, yellowish-brown, green and light green with
occasional pink and red along with white and transparent. Mining in
the Merelani region is extremely harsh and difficult since the material
is found in very heavily metamorphosed layered rock requiring intense
laboring. In addition to the many climatic hardships in the short 24
years of existence of this deposit, the mining area has experienced
political unrest and revolts, tribal fighting for control, civil
unrest, infighting over claims, constant insects, extremely poor mine
safety, cholera epidemics, flooding, feudalistic overlords (working
miners in poverty while paying them next to nothing). Many fine
crystals have been discovered at this one and only know source.
Tanzanite's strong pleochroism (the ability of the crystal to exhibit color changes when rotated in light-although lost in heat treating), is a real asset to the natural stone's brilliance when faceted and polished. Larger crystals that will allow 4 carat finished gemstones are quite rare, and the largest flawless tanzanite (found to date) of 122.7 carats finished, is currently in the Smithsonian Institution's Gem Collection. Most crystals from the mine are either sent to nearby cutters in Africa or shipped to Belgium or Germany for finishing, with India being the largest cutter today. Although relatively soft, when first discovered it was suggested to not be mounted in rings where the gems could easily be scratched or broken, so extreme care in wear and cleaning is highly recommended. Current prices for the deep rich blue, violet purple gemstones vary from $650 to $1,000 per carat depending on clarity and the gem's evident pleochroism characteristics. Fact: 1) The deeper the color and clarity the more expensive the stone per carat weight. Fact: 2) It was recently voted as a new official birthstone (the very first in over 95 years), for the month of December symbolizing prosperity along with Turquoise, Blue Zircon and Blue Topaz.
