Tanzanite Information Part 1
As you probably already read the teaser article on tanzanite information in Section 1, tanzanite is only found in one place in the entire world. It is found in the area surrounding Mount Kilimanjaro, which is a volcano that has deposited many rich layers of metamorphic rock throughout the ages. The locals mine tanzanite with pick axes and shovels. Tanzanite crystals are unearthed demonstrating a dingey yellowish-brown color for the most part. The rough tanzanite crystals are put into crucibles and endure heat treatment at 500+ degrees celcius. When heat treating tanzanite, the prayer of every miner is that they not have any "cracklers" in the pot when heat treatment is completed. The rough tanzanite turns its permanent, beautiful purplish blue color. Sometimes, this heat treatment is done after facetting, depending upon the quality of the rough. These rough tanzanite gems are then faceted into various shapes and then marketed to dealers who wholesale the finished gems to jewelry manufacturers and retailers. Tanzanite colors occur in various shades of gray, brown, violet, blue, reddish-purple, and tints of green. There is another discussion in Section 4 on the many different colors of tanzanite, though the standard in fine coloration in tanzanite has been, and probably always will be...purplish blue, where blue is the dominant color with purple flashes see throughout the stone.
Tanzanite is simply the crystalline form of the mineral zoisite. Zoisite, Ca2Al3(SiO4)3(OH), hydrous calcium aluminum silicate, is a grayish or whitish mineral occurring in orthorhombic, prismatic crystals , also in columnar masses . It is a silicate of alumina and lime , and is allied to epidote . Origin: After its discoverer, Von Zois, an Austrian mineralogist (Source: Websters Dictionary). The chemical structure of tanzanite is identical to that of zoisite, therefore, zoisite = tanzanite, except for the fact that tanzanite is specifically referenced as the crystalline form. Please notice that zoisite occurs naturally as a "gray, brown, or pink mineral". As tanzanite comes out of the ground, it customarily possesses these colors until is is heated to just over 500 degrees celcius for a period of time. Only then does crystalline zoisite turn to its blue color ~ Tanzanite! There are tanzanite crystals which DO come out of the ground with their beautiful blue color. This is the result of the mineral having already been heated naturally in the earth. After all, Mount Kilimanjaro is a volcano and the surrounding land has endured tremendous heat periodically, and, as a result...has naturally produced blue tanzanite.
Only found in one place and mined at great depths beneath the scorching land surrounding the foothills of Mount Kilimanjaro in Tanzania (Africa), tanzanite has become a highly-prized gemstone and sought after by scores or individuals and collectors. It is mined with primitive tools, for the most part, by local tribesmen; however, much of the mines' revenues are being reinvested into equipment which is making the recovery of this enchanting gemstone much more efficient and less labor-intensive.
If you ask any colored gemstone connoisseur, they will tell you that tanzanite is becoming the most desired gem in the United States. We also see this trend manifesting itself in Europe. American and European designers, collectors and jewelry manufacturers are keenly aware that with only one relatively tiny source in Tanzania, tanzanite pricing fluctuations are sometimes extreme and go with the current news and season of the year. In fact, we have seen prices of fine tanzanite more than double within the last 24 months. Please see our other discussion on tanzanite pricing.
It is tanzanite's color and relative scarcity which has caused these dramatic price fluctuations. We all remember the days when one could purchase a very deeply colored tanzanite for around $1000 per carat. There were even smaller tanzanites in the 1 to 2 carat range that had rich color. Just try finding one of these today! These tanzanites were mined mostly in the Block D area. This area has since been depleted and new shafts have been opened. The color being produced by these new shafts is not quite what Block D produced. This notwithstanding, much richly-colored tanzanite is still being produced and is available.
Also, related to color, many people are astounded by the seeming glow of fine tanzanite under natural diffuse light. This is due to the fact that tanzanite is pleochroic, which simply refers to the property possessed by tanzanite of exhibiting different colors when viewed along different axes. In tanzanite's case we see blue, violet, and red. It is no wonder why tanzanite has its appeal in the market today.
With the current supply of tanzanite being "controlled" by the mine owners, prices are expected to continue to increase over time. In fact, many projections indicate that some day tanzanite could be the most expensive gemstone on earth. The opportunity exists today to purchase tanzanite relatively inexpensively (even at $600 to $700 per carat) when compared to the prices of fine rubies, sapphires and alexandrites which sometimes sell into the $1000's per carat.
If you have additional tanzanite information you would like to share with us, please email it to us. You never know, you might just see your contribution on tanzanite information on our site.