Tanzanite is a blue-purple flavor of the mineral zoisite and is named after its country of origin, Tanzania. Found mostly in Mount Kilimanjaro, tanzanite is one of the rarest of gemstones. Let’s see how you should go about evaluating the quality of this beautiful stone before you buy it.
Tanzanite Color Grading
Tanzanite is unique in that it changes colors depending on the light. It’s bluer under fluorescent light and more violet under incandescent light, and you can also see shades of red and brown in it.
A high-quality tanzanite stone should be deep blue/dark violet. Stones that have a light color are considered low quality.
Even if you like them, make sure you don’t pay top dollar for them (at least not as much as what the deep blue stones are sold for).
You should keep in mind that the color of almost all tanzanite available is a result of heat treatment.
This is why it is not recommended to clean this stone with ultrasonic or steam cleaners. (Wash it with warm, soapy water and a soft cloth instead of using harsh cleaners.)
Also, make sure your tanzanite is not exposed to thermal shock (this can happen when a jeweler uses a torch to repair your ring or other jewelry).
Durability: Tanzanite’s Weak Spot
Tanzanite is not a very hard stone. (It is 6.5-7 on the Mohs scale, and emerald and amethyst, for example, are harder and can scratch it.)
For this reason, you should inspect the surface of the tanzanite stone you are about to buy. Be on the lookout for chips, cracks, nicks or any other surface flaws.
Since tanzanite is relatively brittle, it is not the best choice for everyday wear, especially when it comes to rings or bracelets, which are often bumped and hit.
If you are buying a tanzanite ring, make sure it is set in a well-protected mounting (a bezel setting is a good choice). Avoid prong settings, especially those with fewer prongs.
Since tanzanite should not be exposed to jostling due to the stone’s cleavage potential, a better option is to wear tanzanite on earrings or on a necklace pendant, especially for people who lead an active lifestyle.
Evaluating Tanzanite for Clarity
Gemstones are assigned a classification based on whether there are many natural flaws usually visible in them.
A Type I gemstone is very clean, with no inclusions (structural imperfections). A Type III, by contrast, has obvious imperfections.
Because it is a Type I gemstone, tanzanite is expected to be visibly flawless. Use the eye-clean standard to assess the quality of a tanzanite stone: There should be no imperfections visible to the naked eye.
Tanzanite stones with inclusions should be deeply discounted. A blue stone with violet accents is reputed to be the highest quality tanzanite available.
Wearing Tanzanite: Settings and Styles
As mentioned above, earrings and pendants are safe and popular settings for tanzanite. If you do want a tanzanite ring, however, look for a low setting that will protect as well as show off the colorful stone.
Bezel settings are the perfect choice for tanzanite. They will hold the stone securely while allowing it enough prominence to shine.
Wear tanzanite when you want to make a bold color statement. Speaking of color, tanzanite, as a colored gemstone, is rare in its ability to complement everyone.
Complexions that look sallow next to green or flushed in proximity to red brighten in the presence of tanzanite’s vivid blue hues. Be assured that the stone will complement you.
When well-taken care of, tanzanite is a beautiful, rare stone with unique, brilliant color. Discovered less than a century ago but mined in only one location on earth, tanzanite is a stone to be treasured.