TANZANITE

Tanzanite has quickly taken the gemstone and jewellery trade by storm with its beautiful violet & blue hues. These colors closely resemble those of the some of the finest sapphires. The name “Tanzanite” was given to these gemstones by the jewellery company Tiffany&Co who named them after the only country known to produce them.

AN INTRODUCTION TO TANZANITE

True tanzanites are only found in a small region of Tanzania close to Mt Kilimanjaro called the Merelani Hills, the nearest town is Arusha. The scientific name for Tanzanite is actually blue Zoisite, Zoisites are also found in places such as Pakistan but only Tanzania produces the intense colors that these gemstones have become so well known for.

As the story goes, Tanzanites weren’t discovered until 1967 when Maasai herders were walking the Merelani Hills and stumbled upon a handful of intensely colored gem crystals. When they decided to return to the location to look for more of these crystals they only found crystals which were dark brown in color. Disappointment set in and after enjoying the warmth of an evening fire one of the herders tossed some of the crystals into the smouldering embers that remained before going to bed. Upon waking up the next morning amazement set in when they found out these once brown crystals had now turned vivid violetish blue due to the heat.

Tanzanites are rare in two different ways; they are both geologically rare and physically rare. They are geologically rare because they're only found in one small area, an physically rare because even in that small area production is low due to lack of availability and difficulty mining there. Some tanzanite mines reach depths of an astonishing 1400 meters below surface level!

Every now and then circumstances will be just right for a tanzanite crystal to actually turn a vivid pink or even an almost “Tsavorite” green. These are far rarer than blue tanzanites and are also considerably more valuable.

Almost all tanzanites are heated to remove undesirable secondary colors, such as yellow or brown, and turn the gemstones a vibrant blue or violet. Tanzanite is one of very few gemstones where the presence of treatment doesn’t actually affect the price as it is generally an accepted one.

INTERESTING FACTS

Tanzanites when spared from treatment are what is known as a “trichroic” (three colored) gemstone or crystal and will display three distinct different colors depending on the angle it is viewed in. Typically showing a violet and a blue hue along the A & B Axis. Whereas the C Axis will display a burgundy red hue. When heated, the same tanzanite specimen will still display the violet and blue hue, but will lose the Burgundy red hue as it turns “dichroic” (two colored).

Tanzanite crystals belong to the orthorhombic crystal system and usually form into very well defined chisel shaped crystals. Back in 2020, two giant tanzanite crystals were found, the larger of the two weighing approximately 9.27kg, making it the largest tanzanite ever found!