The discovery of tanzanite
Compared to other gemstones, tanzanite has only been available for purchase for a short time.
The discovery of this gemstone is well documented and dates back to a relatively recent time. There are two men who independently claim to have discovered tanzanite. One of them is Manuel D'Souza, an Indian tailor. He mined the blue gemstones in Tanzania from 1967 onwards, believing them to be sapphires. It was soon identified as a bright blue zoisite variant.
A miner, Ndugu Jumanne M. Ngoma (his Swahili name means “making music on Tuesday”), also heard about this. He had also discovered blue gemstones and given them to a gemstone dealer in Nairobi who wanted to examine the stones (allegedly 5 kg). However, Ngoma has not heard from this dealer. He turned to a Mr. Bill, who found out that the stones were a new variety of the mineral zoisite. Unfortunately, there is no market for it yet. When the miner heard that someone else was claiming to have discovered the blue gemstone, he pulled out all the stops. He finally received proof that he had discovered tanzanite: a certificate issued by the Tanzanian Ministry of Mines. However, that was all that remained of his find: he did not profit from it and continued to work as a laborer in a gypsum mine.
From blue zoisite to tanzanite
When blue zoisite was discovered, there was actually no market for it. This changed when Tiffany & Co. became Manuel D'Souza's distribution partner. The company recognized an advantage in the similarity between the expensive blue sapphire and blue zoisite. However, the name zoisite sounded too much like the English word for suicide – not a good prerequisite for sales. Therefore, it was decided to rename it. The blue zoisite became the “Tanzanite”.
Tanzanite: Limited occurrence
Since its discovery, tanzanite has only been mined in Tanzania. In 1971, the mines were nationalized and divided into blocks. The largest of these blocks produces around 2.7 million carats of tanzanite annually. However, according to an independent study conducted in 2012, the tanzanite deposit could be depleted as early as 2042. This could lead to an increase in the value of the gemstone. It may therefore be worthwhile to buy a tanzanite as an investment.
Tanzanite and its blue color
Tanzanite is a transparent, sapphire-blue form of the mineral zoisite. This mineral was already known in the 18th century, but not in blue. Tanzanite owes its color to traces of vanadium combined with extreme heat. Its hues range from light blue to dark ultramarine blue with violet undertones.
When viewed from different angles, tanzanite displays different hues. This effect is called pleochroism.
The gemstone from Tanzania
Tanzanite is mined exclusively in Tanzania, near Mount Kilimanjaro. In some mines, work is done mainly with muscle power and pneumatic hammers, and now at considerable depths. This is because the gemstone is hardly ever found near the surface, but usually only at depths of around 80 meters or more. Other mines, on the other hand, use modern equipment and dig to depths of almost a kilometer.
Use: For jewelry or as an investment
As already mentioned, tanzanite could be a good investment. It can be assumed that the limited occurrence of this gemstone will be exhausted in the near future. Then this gemstone will probably be of high value.
Of course, you can also have this gemstone made into unique pieces of jewelry. It is suitable for rings, bracelets, necklaces or colliers in silver, white or yellow gold. It can be combined with other colored gemstones, but it is usually found alone or in combination with diamonds. It is often used for engagement rings as an alternative to blue sapphire. This makes use of the symbolism of the color blue, which stands for loyalty and harmony.
According to the American Gem Society, tanzanite is the birthstone of December and therefore ideal as a gift for those born in that month.
Tanzanite: gemstone hardness & heat treatment
Most tanzanites are heat-treated. This minimizes brown tones in the stone and highlights the blue tones.
This gemstone has a hardness of 6.5 to 7 on the Mohs scale. Although this makes it softer than sapphire (Mohs hardness of 9), it is still hard enough to be used in any type of jewelry.
Most common cuts: From faceted cuts to cabochon
The beautiful shades of blue in this gemstone are shown off to their best advantage in faceted cuts. The round or oval brilliant cut, pear-shaped or mixed cuts are popular. However, square cuts, such as the octagonal emerald cut, are also possible.
Tanzanite is also cut into round or pear-shaped cabochons.
