What Is Tanzanite and What Makes It So Rare?
The Sapphire Merchant custom Tanzanite and Diamond Ring
Table of Contents
- What is Tanzanite Zoisite?
- The Recent Discovery of Tanzanite
- Is Tanzanite Heated?
- Famous Tanzanite Jewellery Pieces
- Is Tanzanite Suitable for an Engagement Ring?
- Will the Tanzanite Mine Run out?
Tanzanite is a highly valued precious gemstone belonging to the Zoisite family. Legend tells it that in 1967, herders from the Maasai tribe of Tanzania found bright blue crystals after a bush fire charred the earth in the Merelani Hills near Arusha, Tanzania. The intense heat from the fire is believed to have altered brownish zoisite crystals, transforming them into their striking blue-violet hues. The tribesmen brought the crystals to Manuel d'Souza, a local prospector, and this prompted him to register claims over the area in conjunction with the Tanzanian government. Initially, D'Souza thought he was dealing with a discovery of sapphires; however, after gemological testing, the mineral in question was identified as a new discovery of blue Zoisite.
1. What is Tanzanite?
Tanzanite, or 'Blue-violet Zoisite' as it is known by its scientific name, is a calcium aluminium hydroxyl sorosilicate mineral that gets its unique and fascinating blue colour from small amounts of vanadium inside the crystal.
The refractive index (or brilliance) is 1.69 - 1.70, which sits above emerald and below sapphire. The higher the refractive index, the brighter the sparkle. When sitting next to a sapphire of similar colour, clarity, and size, Tanzanite often has a deeper, more intense violetish-blue.
Tanzanite is a durable gemstone, rated 6.5 on the Mohs scale of hardness, about the same as steel or granite. This durability ensures its quality and longevity, making it a reliable choice for jewellery.
"The most beautiful blue stone to be discovered in 2,000 years." ~ Eddie LeVian (CEO of Le Vian Jewelry)
Tanzanite Gemstones in Various Cuts and Colour Shades
What is Zoisite?
The name Tanzanite is applied to Zoisite, which is blue and violet in colour hue. These gemstones have almost always undergone heat treatment to achieve this colour spectrum. Very occasionally, finds are made in the Tanzanite mining area of Zoisite that are unheated, display phenomenal clarity and come in unique colours such as green, yellow and vivid purple. These rare collectors' gemstones are graded as Zoisite rather than the trade name Tanzanite. The rarest Zoisite colours are, in order: solid green, pink, purple, gray, and bright yellow. Higher colour saturation and deeper the colour in any Zoisites equals a greater value
2. The Recent Discovery of Tanzanite
Tanzanite was first "officially" discovered in 1967 near Mount Kilimanjaro in Tanzania. The late Manuel D'Souza, a famed gemologist, was given blue and green crystal samples from Maasai tribe members, who claimed more was scattered throughout the earth on a piece of land southwest of Mount Kilimanjaro. He was taken to the location, whereupon further prospecting, he thought he had found evidence of blue sapphires or possibly peridot. Incredibly, D'Souza had discovered something unique and extraordinary. Samples were collected and sent away for testing. It was too soft to be sapphire and had visual properties different from a sapphire. Laboratory testing confirmed that it was Zoisite, a blue variety that had never been seen before. According to Tiffany and Co., Tanzanite was hailed as the most breathtaking blue gemstone discovery in over 2,000 years!
Maasai Tribemen made the initial discovery of Tanzanite
Where is Tanzanite Mined?
When initially discovered, the land was so rich with Tanzanite that the crystal could be collected from the topsoil.
Now, mining operations use shafts and tunnels that burrow up to 1000 meters deep. The mining area is divided into 4 blocks. Block A and Block C are mined by large operators funded by foreign investment, and Block B and Block D are reserved for small-scale, local miners. Legend has it that the finest Tanzanite crystals are found in Block D.
Each block has been given to a particular interest group, with Block A and C going to mining companies and Block B and D going to local miners. This system of splitting the mining activity up between international companies and local miners allows more of the wealth generated by mining to go to the men and women who work in and near the mines.
Said to be a thousand times rarer than diamond, the mines are suspected of holding over 21 metric tonnes of Tanzanite. Mining is estimated to last until the 2040s when the mines might start drying out.
Who Named Tanzanite?
Tanzanite was originally called Blue-violet Zoisite. Henry Platt, the president of Tiffany and Co. at the time, recognised its marketing potential and sought a name that would highlight its exclusive origin and rarity. He rebranded the newly discovered jewel from Blue-violet Zoisite to the more fitting Tanzanite, a nod to its single geographic origin. Tiffany & Co.'s promotion of Tanzanite under Platt's leadership was instrumental in introducing it to the global market and securing its place as one of the most beloved coloured gemstones available today.
3. Is Tanzanite Heated?
Nearly all strong purple and purplish blue Tanzanite has undergone heat treatment to clarify the crystal and enrich the colour. When heated to 370 - 390 degrees Celsius, for approximately 30 minutes, the yellow and brown tints vanish, and the blue deepens. Before undergoing the heat process, the Tanzanite rough is carefully examined to ensure it is free from any cracks, inclusions or bubbles. Tanzanite is prone to shattering and only tolerates heat treatment if the crystal is clean and uncompromised.
Trichroism in Tanzanite?
Tanzanite is Trichroic and forms as a brownish crystal that displays three colours. Trichroism means that as light enters this anisotropic crystal, it gets refracted on different paths, with different colour absorption on each of the three optical axes. As a result of this phenomenon, a range of colours have been observed in various specimens. Trichroic specimens are sometimes called Mermaid Tanzanite as they exhibit grey, brown, purple, yellow and green colour tones.
What is Dichroism in Tanzanite?
After standard heat treatment, Tanzanite changes from trichroic to dichroic, three to two colours. The dichroic colours range from violet through bluish-violet to indigo and violetish-blue to blue.
What is Pleochroism in Tanzanite?
Pleochroism overaches the terms dichroism and trichroism and describes both phenomena. The colours seen in the Tanzanite depend on the viewing angle and the wavelength of light. Testing for pleochroism is a laboratory test that can help identify Tanzanite from other similar coloured gemstones. A dichroscope is used to test for pleochroism.
4. Famous Tanzanite Jewellery Pieces
The Queen of Mount Kilimanjaro Tiara
The Queen of Mount Kilimanjaro Tiara is one of the most notable Tanzanite jewellery pieces. This astounding tiara is held in the private collection of former Apple president Michel Scott. The centrepiece of this exquisite crown is a 242-carat faceted Tanzanite in a cushion cut. Additionally, the tiara features 803 tsavorites, a vivid green grossular garnet mined only in the Merelani region of Tanzania, the same area where the Tanzanite blocks are located. In addition to the tsavorites, the tiara features 913 diamonds, set in a sinuous pattern to resemble a hooded King Cobra snake.
Belle's Necklace
In collaboration with Harrod's and Disney, Chopard created the magical Belle Necklace for the Swiss jewellery house. Drawing inspiration from Beauty and the Beast, the Belle Necklace showcases a captivating blend of blue and pink sapphires, amethysts, and diamonds in an array of carat sizes and shapes. The central gemstone is a flawless 69-carat pear-shaped tanzanite. The Belle necklace was created in collar style with 18k gold filigree work wrapping around the treasure trove of natural precious gemstones. Valued at over 1 million USD, this necklace is fit for a princess.
What Month is Tanzanite the Birthstone Of?
Tanzanite is the birthstone of December!.Very few gemstones have had as much of an impact on the gemstone industry in recent history as Tanzanite. The American Gem Trade Association (AGTA) made a decision in 2002 to add Tanzanite as December's birthstone alongside turquoise and zircon. This marked the first addition to the modern birthstone list since it was standardised in 1912.
5. Is Tanzanite Suitable for an Engagement Ring?
Tanzanite can be used as an engagement ring gemstone. However, one must remember that it is less durable than other precious gemstones. The design style should be considered, and a setting that helps protect the gemstone from impact is the most optimal. Tanzanite works well framed with diamonds and makes an extraordinary centrepiece for an engagement ring, cocktail ring, or pendant.
Custom Tanzanite Jewellery Design
The Sapphire Merchant has created some exceptional custom Tanzanite jewellery pieces for our clientele, including Tanzanite engagement rings. Tanzanite is an excellent option for people looking for a sizeable precious gemstone with deep, vibrant blue and violet hues. Large and clean cuts of Tanzanite look similar to sapphire, making it an attractive alternative to achieving a luxurious, high-end custom jewellery piece, but with a precious gemstone that is more unique than well-known sapphire. On a side note, putting Tanzanite-set jewellery in an ultrasonic cleaner is not recommended, as this may cause the gemstone to fracture or break.
A Tanzanite Commemorative Ring
A recent custom jewellery masterpiece is this 8.96ct GIA-certified Tanzanite from Block D. In a perfect asscher cut, our client wanted something simple, where the Tanzanite was the star of the jewellery piece. The ring was commissioned to commemorate a special person in her life, and the gemstone was chosen to symbolise that person. This functional and beautiful design was finished in 18k white gold, with bezel detail down the band. The result is an elegant Tanzanite cocktail ring that will be admired and loved for many years to come.
A Tanzanite Cocktail Ring
This luxurious Tanzanite ring was designed exclusively by The Sapphire Merchant and features an extraordinary 6.90ct GIA-certified Tanzanite from Block D. We discovered this Tanzanite on a 2023 buying trip to Bangkok. When it crossed our desk, its perfect clarity, rich colour and excellent cut and polish captivated us. The gem rough had been purchased in Tanzania from Maasai gem dealers by a gemologist with whom we work in close collaboration with. He had it expertly faceted in Bangkok, and when he shared the piece with us, it was a simple decision to acquire it for our collection. Shortly after returning to New Zealand, it inspired the design of this exclusive ring. To ensure the protection of the Tanzanite, we fashioned a sensational halo of D-Colour VVS1 diamonds, which seamlessly cradle the gemstone and then gracefully meander onto the shank. The ring is elegantly crafted in 18k white gold.
6. Will the Tanzanite Mine Run Out?
Tanzanite is a rare and beautiful gemstone. It's only found in one place on Earth, which only holds a limited amount. Unless another mine is located, the cost of Tanzanite will increase as mining activity starts to slow down. If an alternative mine is not located again, Tanzanite will have run its course, and those fortunate enough to get their hands on one of these high-quality gemstones will be one of the few to hold such a beautiful piece of the Earth. Once a mine runs out, then the only gems available are those that come back into circulation from private collections and estate jewellery pieces.
Buying a Tanzanite
Browse our extraordinary collection of Tanzanite, each one a rare and unique treasure. If you have a particular requirement, we have access to the most exquisite and hard-to-find Tanzanite pieces through our incredible network of the world's best gem dealers.
We offer in-person viewings for New Zealand residents and virtual viewings for our international clients, ensuring you have access to the most exclusive gemstones.
Our design process is a true collaboration, entwining your vision with our creativity. Upon choosing your precious gemstone, we gather information to conceptualise your vision. Using computer-aided design (CAD) technology, we transform your jewellery idea into a detailed 3D model. You have the flexibility to customise every aspect of your design idea, and we will guide you through this creative process, ensuring your unique vision is brought to life.
Once your design is perfected, our skilled team of jewellery artisans brings your piece to life with meticulous attention to detail, ensuring the highest-quality finish. With The Sapphire Merchant, you get a breathtaking piece of jewellery and a memorable experience tailored to your requirements. We will create for you a cherished heirloom that will be treasured for generations to come.
