Tanzanite - What you need to know
All Tanzanite has Value. From the palest to the deepest hues, this Zoisite gemstone is sought after for its beauty and comparable rarity. For example, the turquoise we all love is mined in many countries. While we may have run out of opportunities to buy from closed mines, there’s always another mine somewhere. Not true with Tanzanite. If you’ve seen a lot of Tanzanite, you know it can look quite different. So how do you value it?
Tanzanite Grading. Full Tanzanite grading is much like diamonds. I’m not a certified gemologist, so I’m basically discussing color. If you want investment grade Tanzanite – go for the exceptional or deep colors shown on the chart below with a good certification. I do not currently use investment grade Tanzanite, which runs 300 – 600+ per faceted stone carat, depending on cut, clarity, color. All other things equal, the price per carat weight increases with larger stones. For example, a 6-carat stone will be more than twice the cost of a comparable 3 carat stone.
PLEASE, if you see something in the deep to exceptional color range for less – just run. If it says it’s certified, pay attention to the certifier. I saw something on Etsy that was supposedly a “certified” 9 carat, natural Tanzanite gemstone in a deep color with great saturation and looking to be a good cut (small picture – who knows) for about $40. I looked up the certifier. A legitimate business in India known for writing certifications to the seller’s specifications, not the stone. The best gem certificates in the US are those issued by the Gemological Institute of America (GIA), International Gemological Institute (IGI), and American Gem Society (AGS).
There are multiple grading systems but an easy, beginner one to use is AAAA, AAA, AA, and A, which can be determined, in part, using the color chart below, tope row is AAAA, second row is AAA, combining rows 3 & 4 for AA and 5 & 6 for A. Just keep in mind that there is more to quality than the color.
Is this the only color? No, in addition to purple, blue and violet blue, it can also be green or golden green. When it first comes out of the dirt, prior to heating, it can be greyish.
Why is it so expensive?
Well, it’s beautiful for one thing. If a stone has great value but you don’t love looking at it or wearing it, what’s the point unless you are an investment collector?
The main thing is that it is a one-source gemstone, found only in the Mount Kilimanjaro region of Tanzania, Africa. Scarcity breeds increase in demand. There were once several very large mining operations in the area. Last I checked, there is only one large operation and a few small, independent miners. Apparently, the large operations reached the point that they had acquired all the cost-effective rough and it became too expensive and unsafe to continue. Can you buy it at a reasonable price today? Yes, but it’s getting harder. Even the grade I can afford to offer you has gone up and I expect it to continue. The Tanzanite jewelry you buy from me may not be a chunk of your retirement portfolio but it’s a pretty sure thing that it will never go down in value.
Another special thing about Tanzanite is that this crystal Zoisite stone’s appearance is influenced greatly by its pleochroism, which is the ability of a gemstone to show different colors when viewed in different crystal directions. It can also look more blue or purple, depending on the light source.
Durability
Tanzanite shows up on the Mohs scale (measuring hardness) at a 6.4 t0 7 – just behind diamonds, rubies, and topaz so it’s suitable for rings as well as necklaces and earrings. That color we all love comes from heat treatment which has the added value of exposing any stone fractures, so you are better assured of no internal fractures in your stones.
Bottom line – buy from trusted sellers and verify any costly stones via certification.
If you are investing a large chunk of money, the certification cost is worth it. Otherwise, just love your stones and wear them proudly!