A Deep Dive Into The Value Of Tanzanite
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Tanzanite, with its mesmerizing violet-blue hues, has captivated the world of jewellery enthusiasts since its discovery. Found exclusively in the Merelani foothills of Mount Kilimanjaro in Tanzania, this rare gemstone has quickly become a symbol of luxury and sophistication.
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What is Tanzanite?
Tanzanite is a gemstone, specifically, the blue variety of zoisite, in its most basic form is a mineral, specifically a calcium aluminium hydroxy sorosilicate.
The Origins Of Tanzanite
Tanzanite became known to the world in 1967. Lightning that set fire to the grasslands turned brown zoisite to a blue colour on the surface where Maasai tribesmen found the gem. Initially thought to be a new variety of sapphire, Manuel D'Souza was shown the location of the crystals by the Maasai herders and he staked the first mining claim but in 1971 all the mines were nationalized by the Tanzanian government.
In the early 1970s Henry Platt, the President of Tiffany’s, was shown blue zoisite. Feeling the name zoisite would not be appealing to women he christened blue zoisite with the name Tanzanite after its country of origin. Henry Platt rightfully declared tanzanite to be “the most beautiful blue gemstone to be discovered in 2000 years.” They proudly stated that Tanzanite could only be found in two places on earth, in Tanzania and at Tiffany’s.
The early years of tanzanite were controlled by Tiffany & Co who were the early promoters of tanzanite. Prices were high as Tiffany commanded a monopoly and supply out of the fledgling mines was low and sporadic.
Tanzanite rarity & the mines in Tanzania:
Tanzanite is considered by many to be a thousand times rarer than diamonds, and it's only found in one place on the planet in Tanzania. It's an approximately 12 square kilometre mining area. These mines are around 3000 feet or more into the ground. And for tanzanite, that's it. Once the supply is gone, there will be no more to be had.
Extensive geological research indicates that the chances of finding tanzanite in another part of the world are less than one in a million.
The Tanzanian government has built a wall completely around the Tanzanite mines. Much of the rough previously left the country through neighbouring Kenya to avoid taxation. They will attempt to have all trading of rough handled through a government office within the mines. These changes taking place in Tanzania make tanzanite a very good investment stone and prices in Arusha are going through the roof.
Countless hours of labour are required for a gem to reach customers from the mine which contributes towards Tanzanite value & other factors affecting value include the depth of colour, quality of colour in daylight and in incandescent lighting, the clarity of the stone, the type of cut, quality of cut and polish & the demand for tanzanite.
Now let’s look at the four Cs of quality of tanzanite in more detail:
The Four Cs Of Quality
Carat Value Tanzanite
As the size of tanzanite increases - the price per carat increases accordingly.
Carat weight has less of a value effect on tanzanite than on other gems like ruby, sapphire, emerald or diamond. Large gemstones of 10-20 carats are not as rare for tanzanite as they are for these other gemstones.
Tanzanite colour is less saturated in smaller sizes. Gems must be above five carats in size to have fine colour. It's just very hard to get smaller stones in high quality. The 5 to 15 carat stones are where you can get the finest gems and regularly. When it gets big enough to these sizes it displays the deep vivid colours that you're looking for in tanzanite.
As such, Tanzanite prices do not increase rapidly on a per carat basis at different carat brackets. A 3 carat stone of high quality could be of a similar price per carat as a stone of 10 carats in similar quality.
Tanzanite value is very much linked to rarity - the finer the colour/clarity/cutting grade the higher the price.
Tanzanite Colour
Deep saturated violet blue or blue violet are the most valuable tanzanite colours. Paler hues are more commonly found. The deepest and purest hues of blue are the most valued ones. Blue and purple tanzanite are both very valuable but the bluer the tanzanite the more sought after it is.
Tanzanite hue - First of all the hue of the Tanzanite is considered. This is the actual colour sensation the human eye perceives when it looks at the stone. The bluest hues are among the rarest.
Tanzanite Saturation - Saturation is arguably the most important component of colour. It is in effect the strength of the hue itself. The highest saturation, the most vivid stone is the most valued.
Tanzanite tone - Tone is effectively how light or dark a stone is. While many appreciate pale stones, slightly darker stones without being too dark are valued higher.
The rules of colour generally follow the laws of nature in that strong, vivid colours are attractors. Human beings gravitate towards the deepest, most saturated colours in gemstones, it is part of our psyche. These colours occur much rarer in nature too and the finest, most valuable grades represent only 1% of production.
This has been translated into a value system for gemstones, Tanzanite included, whereby the most vivid and deeply saturated colours are more highly coveted.
Pleochroism
Pleochroism is the ability to show different colours in different directions of the crystal. Tanzanite is a rare crystal in that it is a trichroic gemstone. This is because Tanzanite shows blue in one direction, purple in another direction and finally yellow in the last direction. This makes it a very colourful gemstone and why you see so many different colours of Tanzanite. A characteristic that contributes to Tanzanite’s beauty.
Fancy colour tanzanite
Tanzanite stones can be found in many colours and colour combinations. These stones are extremely rare and found in very small quantities, with pink being amongst the rarest and most highly sought by gem collectors. Other colours include peacock (which is blue with a lot of green), yellow, green & peach. Technically these are a colour variety of zoisite not tanzanite.
Colour changers
While most tanzanite will change colour a little bit under different lighting, colour changing tanzanite are different and exhibit strong colour change. They will change colour almost completely from daylight to incandescent lighting and are very rare.
Tanzanite Cut
What matters in terms of cut is the quality of the cut & excellent light.
Badly cut gems can appear very blacked out as there is little internal light reflection. This can make the stone look dark and the sensation of colour is limited to the blackness the eye perceives.
No shape is considered intrinsically more valuable than another. Tanzanite is available in a wide range of shapes but oval cuts are most common. The final shape chosen largely boils down to the shape of the rough tanzanite because the cutter will aim to cut to achieve minimum weight loss and maximum yield.
Tanzanite Clarity
Eye-visible inclusions decrease the value of tanzanite, particularly in lighter coloured stones. The greater the extent to which inclusions are visible, the greater the value of the stone declines. What you are looking for in terms of the highest grades of tanzanite is an eye clean stone.
Tanzanite stones have relatively excellent clarity compared to other gemstones. Emerald, for example, is expected to be heavily included and therefore a perfect eye clean stone is not as important as it for tanzanite. For tanzanite however, you should expect there to be very few visible inclusions in the higher grades.
Why Heat Tanzanite?
In the rough, tanzanite looks more red-brown in colour and then after it's heated it goes to the blue-purple colour we are used to seeing. Tanzanite has blue, purple and yellow in its rough form. And when yellow is removed, it leaves the blue and purple which are very desirable colours for gemstones. The stone effectively changes from trichroic to dichroic, meaning it shows 2 colours instead of 3.
Synthetics
No laboratory has successfully managed to synthesize tanzanite with the same chemical and physical properties.
Imitations of Tanzanite
The closest replica of tanzanite is forsterite. It looks much like tanzanite. Then there's also synthetic sapphires that are coloured to look like tanzanite. You also have low grade stones that are coated. They put a thin layer of a coloured material over the stone, so when you test it, it is a tanzanite, but it has a coat that causes the perceived colour to be deeper.
Doped Heavy Glass & yttrium aluminium garnet are also used in the market to deceive buyers as tanzanite. Synthetic gemstones are allowed in the market but have to be declared that they are synthetics. Synthetic gemstones are typically less valuable than natural gemstones in the marketplace.
Sapphire Vs Tanzanite Prices
A 1 to 3 carat sapphire is generally around 6 times the price of an equivalent sized tanzanite. In the 5-10 carat price range the price difference can be 10 times the price. So tanzanite has a huge benefit price wise for a similar beauty.
Tanzanite Demand
Prices of Tanzanite can often change quickly and dramatically. For example, China has been showing more interest in Tanzanite and with the vast market in China, growing demand could have dramatic effects on the price and availability of Tanzanite.
Hardness
Based on the Mohs scale of hardness, Tanzanite is 6.5 to 7 meaning it is a slightly soft gemstone needing to be treated with care, similar to Emerald although less brittle, Diamond is the hardest gemstone, scoring a 10 on the scale.
Tanzanite cleaning and care
Like all precious gemstones, Tanzanite should be treated with care to preserve its beauty and value. You can read more about this in our Tanzanite Buying Guide. Ultrasonic cleaning and abrasive cleaning solutions should be avoided. Tanzanite should be cleaned using a small, soft brush and warm, slightly soapy water.
Gently clean the upper and underside of the Tanzanite, and dry carefully with a soft, clean cloth. Tanzanite should not be exposed to sudden extreme temperatures and should be stored in a protective pouch or box separately from other jewellery. When jewellery is being altered or repaired, the Tanzanite should be removed from its setting beforehand.
2 large stones sold into the millions
In 2020, miners in Tanzania found two large Tanzanite stones. One weighed 20.4 pounds and the other 11.3 pounds. These stones were sold to the Tanzanian government for $3.3 million. This shows how rare and valuable Tanzanite is.
Future value of tanzanite
The finest grades will likely see continued price inflation through low supply due to rarity and high demand. Demand, with time, as jewellers worldwide continue to promote tanzanite’s qualities, will only continue to rise.
The stone's real value as an investment lies in the potential for astronomic prices once it has been mined out. This is what makes the stone an interesting prospect as an investment.
Tanzanite's fairly recent inclusion in the Birthstone list, being named as a birthstone for December, was the first time the list has been altered for many years. An auspicious and important factor in assessing Tanzanite's popularity and hence the demand for this gemstone.
Looking forward, there are a number of factors which may affect prices. China’s recent entrance into the market and growing demand for Tanzanite is a wild card that could affect the price trajectory in coming years.
Final Words
Once the mine is depleted, the world's enormous demand for Tanzanite will only be catered for from what exists in private hands. At that point, Tanzanite values, most especially for the finest material, will be extremely high.