Tanzanite- “Gemstone of a Generation”
By Medha Patel
Belonging to the Zoisite gem family, Tanzanite is one of its own kinds. This unique blue gemstone was naturally created over 550 million years ago, due to the interactions between the tectonic plates (Tanzanite History). To add to its uniqueness, Tanzanite is only found in a stretch of an area that is only 17 square kilometers. This area is known as Merelani hills, approximately 50 kilometers from Arusha town, Tanzania. Moreover, the source of Tanzanite is known to be finite, and thus it is known also known as the “Gemstone of a Generation” (Discover Tanzanite). The supply of Tanzanite remaining is estimated for around 30 years only. This limit means that Tanzanite is a thousand times rarer than diamonds. Hence, the value of Tanzanite is increasing with every passing day (Afrogem | Tanzanites).
Tanzanite is a comparatively recent finding. Ali Juuyawatu, a local Maasai tribesman, found the first Tanzanite crystal, in 1967 July. Enchanted by the blue-violet hue, he shared his discovery with Manuel D’Souza- tailor by profession and prospector by passion. D’Souza was in search of rubies in the region. Initially, D’Souza thought the gem specimen was sapphire; however, gemological tests revealed that the specimen had a more complex crystal structure than that of a sapphire. In addition, the color of the gem specimen was more appealing, more fascinating and more glamorous than any other known gemstone. The photograph below shows Manuel D’Souza, followed by District Secretary for Arusha, Ali Juuyawatu and Daniel Saitore Kaaya (Tanzanite History).
The exotic blue gemstone was given its trade name by the jewelers Tiffany & Co., after the country it originated from. Tiffany heavily promoted the stone in 1968, and it gained popularity overnight among leading jewelry designers and various gem professionals. The popularity was also linked to its physical and chemical properties (Tanzanite History and Lore). In addition, Tanzanite is the birthstone for the month December, and the gem for the 24th anniversary (What Is Tanzanite Gemstone | Tanzanite Stone – GIA).
Characteristics of Tanzanite
Mineral: Zoisite
Chemical Formula: Ca2Al3(SiO4)3(OH)
Color: Blue to violet to bluish purple
Refractive Index: 1.691-1.700
Birefringence: 0.008 – 0.013
Specific Gravity: 3.35
Hardness on Moh’s Scale: 6 – 7
(What Is Tanzanite Gemstone | Tanzanite Stone – GIA)
My recent visit to the Merelani Hills as a part of the Lapidary Class, Tanzania Gemological Center, was very enlightening. We visited one of the large-scale mining companies, which is also the world’s prominent Tanzanite Company- Tanzanite One (Company Overview | Tanzanite One). There we were guided by a couple of engineers through the state-of-the-art facilities. We were given a brief introduction about the company through a power point presentation, which included some historical information and the current state of the company. The power point mentioned that Tanzanite One was formerly known AFGEM- African Gem Resources Limited, a mining company that was based in South Africa. The machines, equipment and the facilities are well developed. The company has employed over 650 people, which includes the staff that works above and below the ground. Moreover, 95% of their staff is Tanzanians. About 200 miners work underground for every shift. Every shift is 8 hours long. In addition to that, the company cares for their employees. Tanzanite One teams up with some doctors from Kilimanjaro Christian Medical Center- KCMC to set up an annual Eye Camp for the miners. After the presentation, we were taken for a tour around the premises to see the various processes.
The tour started with the very first mining site. The whole mining site in located in Block C. The very first mine shaft was dug up during the discovery period of Tanzanite. The soil in that mine shaft was iron rich. Hence, that mineshaft didn’t last long since the soil would collapse due to weathering. Hence, it was decided that mining in that shaft was very risky for the miners since the shaft could collapse at any time.
We continued the tour by visiting one of the mine shafts that had been shut down due to conflicts with other small-scale miners. The small-scale miners were mining towards the Tanzanite One mineshaft. There came a point when the invaders burnt down the facilities around the mineshaft. 
Currently, the mineshaft is locked down and protected with security guards. Later, we were taken to the Winch Room or Hoist Room. The Winch Room is a room that encloses a pulley-like system that is used to haul the soil from underground. In addition, this system is also used to transport dry food to the miners working underground. The conveyance takes about five to six minutes to transport over a distance of 800 meters. The machine is run by a 150KW motor, which has three brakes in case of any emergency- electric brake, hand brake and hydraulic brake. An operator is always stationed at the winch room, during working hours. Before the conveyance process begins or halts, the operator communicates using a bell, or a telephone when necessary. Once the soil from the underground is collected into a truck, it is transported to a separation area.
The separation area consists of a huge machineries, as shown in the image above. First the stones in the soil are sorted by size. The big stones are then crushed into smaller stones by the use of crushing machine. This machine is manually controlled, and it can process up to 64 tons per hour. Later, the separation is based on density, using the dense media separation technique. Anything less th
an 2mm is considered as waste, since it is not economically profitable. We continued by visiting the sorting room. The sorting room is a facility where gemstones are sorted manually into various categories based on color and size. The image on the right shows a person sorting the Tanzanite.
The whole mining process is so well executed. Tanzanite One is known to be the most modernized industry in its locality. The Company ensures that the machinery is well serviced from time to time. They have a workshop near the winch room. This guarantees the safety of the miners and eases the process of mining deeper. From the above-mentioned process, we can relate to the expense of mining Tanzanite.
Tanzanite is such a rare mineral. The area of occurrence makes it unique and the fact that the Tanzanite deposits are finite and limited to next 30 years. That means that every person that owns a Tanzanite today is the first-hand owner of it. As for the future generations, this might be an extinct gem, and may only be owned through family heirloom. Hence, Tanzanite is known as “Gemstone of a generation.”
WORK CITED
“Afrogem | Tanzanites.” Afrogem. Web. 20 Oct. 2015.<http://www.afrogem.co.za/tanzanites/>
“Company Overview | Tanzanite One.” Company Overview | Tanzanite One. Web. 22 Oct. 2015. <http://tanzaniteone.com/company.html>
“Discover Tanzanite | Tanzanite One.” Discover Tanzanite | Tanzanite One. Web. 22 Oct. 2015. <http://www.tanzaniteamerica.com/Tanzanite-History.php>
“Tanzanite History and Lore.” Tanzanite History and Lore. Web. 23 Oct. 2015. <http://www.gia.edu/tanzanite-history-lore>
“Tanzanite History – Tanzanite Discovery, Tanzanite Birthstone, Tanzanite Mine Floods, Tanzania Minerals Act.” Digital Image. Web. 23 October 2015. <http://www.tanzaniteamerica.com/Tanzanite-History.php>
“Tanzanite History – Tanzanite Discovery, Tanzanite Birthstone, Tanzanite Mine Floods, Tanzania Minerals Act.” Tanzanite History – Tanzanite Discovery, Tanzanite Birthstone, Tanzanite Mine Floods, Tanzania Minerals Act. Web. 23 Oct. 2015. <http://www.tanzaniteamerica.com/Tanzanite-History.php>
“What Is Tanzanite Gemstone | Tanzanite Stone – GIA.” What Is Tanzanite Gemstone | Tanzanite Stone – GIA. Web. 23 Oct. 2015 <http://www.gia.edu/tanzanite>
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