Tanzanite (Blue Zoisite) is a rare mineral. It was discovered by Tiffany & Co. in the 1960s and named Tanzanite after the tiny mining area in Tanzania in which it was discovered.

This stone appears blue, violet, or green-yellow to brown, depending on the viewing angle. Gem cutters will cut and polish each stone to make the most of the blue or violet hues. Though most tanzanite is heated to bring out the blue, this treatment produces a stable colour that makes this stone so desirable.

Rare specimens of zoisite exhibit green, yellow, or pink primary hues.

What are AAA or AAA+ grade Tanzanites?

Alpha grading is a commonly heard term in conjunction to grading of gemstones. However it is not actually part of any recognised or documented lab grading system, neither is Alpha grading used at the mining level. It is purely a marketing statement with little objectivity behind it.

OK, so how should we grade Tanzanite?

The Gemological Institute of America is one of the world’s most respected authorities on coloured gemstones and Diamonds. Its grading system is the most universally accepted and widely used worldwide.

The GIA Colour Grading System

The system works by breaking down Tanzanite colour into 3 distinct components, Hue, Tone and Saturation.

In coloured gemstones, the more intense or saturated the colour, the more rare the stone, and the higher its value.

The GIA certificate which comes with each of my Tanzanites, will give you the most widely accepted system in the trade today.

The Tanzanites I have used in my designs are all in the top 1% for cut, clarity and colour. Their vivid and deeply saturated colours are highly coveted.

Is Tanzanite conflict free?

First a bit of background - What are conflict gemstones?

The blockbuster movie Blood Diamond highlighted the fact that some diamonds distributed by otherwise respectable companies had actually been mined in war zones in Africa, such as Sierra Leone, Liberia, the Ivory Coast and Angola, funding militia and wars. Though the UN-sponsored Kimberley Process created a tracking process for diamond roughs and curbed the trade in conflict diamonds, the bad publicity definitely hurt diamond sales, and led to some people prioritising coloured gemstones instead of diamonds.

What about coloured gemstones, are they conflict-free?

80% of coloured gemstones are mined in small or artisanal mining operations, profits in these instances are more likely to go straight back to the local families and communities.

There is nothing like the Kimberley Process in place to certify coloured gemstones as they progress from mine to market, But, simply put, the shorter the supply chain from mine to jeweller, the less chance of funds being misdirected. This is a big subject, so I will write a longer blog post specifically on the ethics of gemstones.

What about Tanzanite?

I purchase my Tanzanite, and many other coloured gemstones from a reputable gem dealer in Kenya, who deals directly with artisan miners and stone cutters in Tanzania. Each stone is sold with international certification, and has been sourced ethically under fair, safe and lawful mining conditions and is conflict-free. The Mining Act 2016 set a royalty of 5% on all exports to be held in trust and distributed to the communities in the mining areas. A lot of the funds so far have been channelled into education and schools as well as hospitals in the area.

Is Tanzanite worth investing in?

The intense violet-blue hues of tanzanite can rival fine blue sapphire at a fraction of the price – and it is a much rarer stone! Occurring only in a small area of Tanzania, this variety of zoisite has become quite prominent.

Any investment has risks, and, the price of tanzanite has fluctuated greatly since its discovery in 1967. The supply of the stone has wavered depending on the political situation in Tanzania. Events such as floods or mining challenges also have an immediate impact upon supply and price. Illegal mining and smuggling have also moved the price of tanzanite. In 2012 and 2013 large numbers of illegal miners entered the tanzanite mining areas and began to aggressively mine the easy-to-access areas. This occurred at a height of tanzanite prices. They then dumped a flood of illegal production into the market, causing a sharp decline in tanzanite prices during the following two years.

When prices change, commercial-grade gems usually experience the greatest price instability. These are the most abundant grades of tanzanite where price competition is highest. However, top-quality stones (such as the stones I invest in, which are in the top 1% of Tanzanite quality), especially those above 2ct, are very rare. As a general rule, they tend to retain their value in down markets and increase in value in rising markets.

As no other source of Tanzanite has been discovered to date, and, at the current rate of mining, estimates suggest that the mines will be depleted within the next 25 years. So now could be a good time to invest in Tanzanite.

Can Tanzanite be worn every day?

Gem and mineral hardness is measured on the Mohs scale, with Diamond being the hardest mineral (10) and Talc being the softest (1). Tanzanite sits at between 6 and 7 on the scale - a similar hardness to Garnet and Moonstone.

Tanzanite is not a gem that should break easily but it can scratch more easily than harder coloured gems like Ruby and Sapphire.

Due to Tanzanite's relative softness, it should be treated with respect. It is generally advised that you should not wear coloured gemstones while doing heavy or rough work (such as cleaning, gardening or performing sports activities) avoid contact with gritty substances and remove whilst swimming due to the chlorine in pools.

Gems with a hardness of 6-7 or greater are quite suitable for rings which are worn occasionally. But for a ring like a wedding or engagement ring, intended for everyday wear over a period of years, a hardness rating of 8-10 (for example Ruby, Sapphire, Spinel, Topaz, Cat’s Eye, Alexandrite or Diamond) is recommended.

When worn, pendants are much more protected than rings, so Tanzanites are fine to wear every day as a pendent. I’d still recommend removing them before sports or swimming, or showering.

On a personal note, I’ve worn Tanzanite jewellery out on many occasions, but treat it more like event/cocktail jewellery. In the Tanzanite Trillion rings I’ve designed, the claws are a little larger to protect the corners of the triangle, and the halo of diamonds surrounding the main stone, also helps to protect the Tanzanite.

To clean Tanzanite, never use an ultrasonic cleaner or steam cleaner (often found in jewellers). The best method is simply to use a toothbrush and warm, soapy water.