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TANZANITE

00775

Locality

Merelani Hills, Lelatema Mountains, Arusha Region, Tanzania.

Dimensions

9.5 cm x 3.6 cm x 4 cm

Weight

341 g

Description & Provenance

Tanzanite is a form of zoisite that was first discovered in Tanzania in 1967. Although a more recent discovery, tanzanite quickly gained popularity as a colorful and attractive gemstone and is now considered one of the most important colored stones in the gem and jewelry industry today. Although not all gem material has resonated with the same importance in the mineral collecting world as it does in the world of jewelry, tanzanite has taken both worlds by storm, establishing itself as fascinating and collectible in both its cut and natural forms.

The golden era of tanzanite production was between 2007-2010 and it was during this time that many specimens and gem rough pieces came to market. Since this influx however, findings have been sporadic, and the last two years have not produced any significant finds for the mines. In addition to sparse discoveries, miners of tanzanite have stated that their already limited resources will most likely be depleted within the next thirty years and noted that difficulties may cease mining even sooner.

Most tanzanites have muddled coloring that consists of a mix of browns, reds, blues and purple. The rarest and most sought-after of all tanzanite crystals are the ones that exhibit an evenly saturated, intense, dark blue coloration. Many, if not most of the tanzanite crystals used in the jewelry industry were once of the muddled variety but have been heat-treated to adjust color consistency and saturation. Heating tanzanite crystals or rough with naturally muddy coloring re-aligns their molecular structures and homogenizes them to a lovely, even, purple tone. While the heat-treated gems are considered beautiful and are wholly acceptable after enhancement, ultimately the naturally derived, dark blue specimens are still considered the pinnacle of desirability by jewelers and mineral collectors alike. The preference for naturally dark blue specimens is not just a matter of color preference but a consideration of the side effects of the color enhancement process. Heating a tanzanite not only alters its overall color, but it also affects its natural ability to express trichroism. Trichroism is the appearance of different colors, dependent on which axis a crystal is viewed. Natural tanzanite specimens exhibit different colors at its X, C and Y axes. In the best examples, the X and Y axes show purple or blue, and the C axis exhibits red. Although cutting tanzanite rough into gemstones will mean the reshaping of its natural form and a difficulty in observing trichroism, discerning a natural tanzanite from an enhanced example is simple. One must only look for the red component (or lack thereof), it will be completely absent from heated pieces. These heated pieces are no longer considered trichroic, but dichroic, a travesty to collectors of high-caliber minerals who treasure natural tanzanite and its incredible characteristics.

This specimen is a spectacular example of tanzanite with outstanding, saturated color. It was acquired directly by Daniel Trinchillo of Mardani Fine Minerals from a Tanzanian dealer who recognized the exceptional quality of the piece and reserved it from the cutting rough. All axes display exceptional color with vivid brilliance and it has smooth, glassy faces with delicate striations on just some its surface area. It is a gorgeous example of tanzanite and stands to become even more rare and collectible as resources become fully depleted in years to come.

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