Tanzanite comes from a mineral variety called zoisite and it was first discovered in 1967. It is named after the country of its origin, Tanzania, which is the only place in the world where this blue or purple blue gemstones are found.
The blue or purple blue color of tanzanite is due to the presence of vanadium in the element zoisite. Tanzanite also exhibits pleochroism, a unique optical phenomenon in which it displays different colors when viewed at different angles and in different light. Blue hues are much more prominent in fluorescent light while purple hues are more visible in incandescent light
Tanzanite measures 7 out of 10 on the Mohs scale of hardness making it relatively less hard than sapphire, ruby and emerald but still strong enough to be used in jewelry such as engagement rings. It's also ideal for lower-contact jewelry such as necklaces and earrings.
Even though tanzanite is a relatively new entrant in the market and doesn’t have a long history as many other gemstones do, it is still associated with virtues such as wisdom, dignity, and truth.
Tanzanite is considered 1000 times rarer than diamonds; it is expected that the mined would probably deplete within the next few decades. In spite of this rarity it is quite an affordable gem when compared particularly with blue sapphires.
Due to its incredible value and vivid colors, it’s been a favorite choice for renowned names in the jewelry industry such as Harry Winston, Inc. and Chopard as well as trendy artists such as Kat Florence and Rodney Rayner.
Tanzanite is the birthstone for the December born and it is also the 24th wedding anniversary gemstone.
The color intensity, clarity, and cut/transparency of a tanzanite are the three key characteristics that determine its quality. The carat weight of a tanzanite is also an important element in determining its price. The price of a tanzanite, like that of any other gemstone, is directly proportional to its quality. These factors are described in detail hereunder along with the overall letter grade system which is used for quality identification.
The color of a tanzanite is the most important quality criterion and it determines the price of the gemstone. The color of a tanzanite ranges from blue to purple blue and violet blue. The color should be well-distributed with a high saturation level and the stone must be transparent. However, as the color in a tanzanite becomes oversaturated and eventually opaque, the price drops substantially. A very light color tanzanite and an overly dark/opaque tanzanite generally command a similar price.
Clarity refers to the presence or absence of internal and external imperfections in a gemstone. Unlike diamonds, color gemstones do not have any universal clarity grading system. We evaluate the clarity of a tanzanite in the following manner.
Transparency refers to the attribute of a gemstone to let the light pass through. The more light passes through, the more transparent the stone. Everyone loves transparent gems because the colors appear vivid. The only problem with higher transparency is that the flaws in the gemstone are more visible as compared to less transparent stone.
The rough of tanzanite is cut in a way to obtain the desired color saturation of the tanzanite since the price is primarily dependent on the color. Lighter material is cut deeper to allow the gem to hold more light and increase saturation, whereas darker material is cut shallower to allow more light to pass through the stone.
Cutting a gemstone requires a high degree of skill which is mastered with years of practice and patience.
Carat (ct) is the primary unit to measure the weight of a gemstone. One carat equals one-fifth of a gram or one gram has five carats. The deep or the shallow cut of a tanzanite will have a bearing on its apparent size thereby making it important to consider other measurements such as length and width which are expressed in millimeters. A 7x5mm Oval can weigh 0.80cts or 1.5cts, depending on its depth and cutting style.
Most of the color gemstones are found in many locations whereas tanzanite is found only in one country- Tanzania. The most known region there is a small mining area near the Merelani Hills. There is no such thing as a tanzanite of a different origin and not originated in Tanzania. Thus, the origin of a tanzanite is a non-factor when it comes to determining its quality.
The vivid rich color of a tanzanite is typically achieved by heating the gemstone at extremely high temperatures. This heating can naturally occur underground or it can be done artificially, There is however no way to determine whether a tanzanite is heated naturally or with a lapidary. Therefore, all tanzanites must be considered heat treated.
A letter grading system is used by several local jewelers to educate their consumers about the quality. We've given here a full description of the grading system used commonly and by us.
| Grading | % of All Tanzanite | Description | |
|---|---|---|---|
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AAAA (Heirloom) | Top 1% | Fine quality gems that are typically found at higher end boutiques. They have rich color, slightly included to eye clean clarity and tend to exhibit nice sparkle. These gems tend to appreciate the most in value over time due to rarity and high demand. |
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AAA (Excellent) | Top 10% | High quality gems that are typically found in high end stores such as on 5th Avenue. They have vivid to medium color and slightly included to very slightly included eye clarity. |
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AA (Very Good) | Top 25% | These gems typically have medium to light color and moderate to slightly included eye clarity. They are usually found at medium to high end jewelers. |
AAAA (Heirloom)
Top 1%
Fine quality gems that are typically found at higher end boutiques. They have rich color, slightly included to eye clean clarity and tend to exhibit nice sparkle. These gems tend to appreciate the most in value over time due to rarity and high demand.
AAA (Excellent)
Top 10%
High quality gems that are typically found in high end stores such as on 5th Avenue. They have vivid to medium color and slightly included to very slightly included eye clarity.
AA (Very Good)
Top 25%
These gems typically have medium to light color and moderate to slightly included eye clarity. They are usually found at medium to high end jewelers.
Tanzanite is a reasonably hard gemstone and doesn’t require much care. But here are a few things that you can do to keep your tanzanite jewelry looking new.
