Tanzanite Buying FAQS

What is “AAA” tanzanite ?

Unlike diamonds -no standard quality grading scales exist for tanzanite. As a result many companies have developed their own quality descriptions, like AAA, AA, A to denote the range of quality of their tanzanite. It is important for consumers to understand that this type of grading is descriptive rather than scientific – and as a result comparing “like for like” becomes a difficult process.

Is “D Block tanzanite” better than tanzanite mined in the other blocks?

The short answer is no. Barely covering eight square miles, the tanzanite deposit has been divided into four blocks by the Tanzanian government—Blocks A through D. Block D simply refers to the area from which material is mined. Traditionally ( late 1960’6 & early 1970’s) larger quantities of the best material were found in Block D, so the term became linked with the top grade. However, fine tanzanite comes from all blocks. This term is beloved by online sellers who wish to promote their tanzanite as superior, though it has no scientific basis and is not a guarantee of quality or value.

Tanzanite Mining Area – showing blocks “A” to “D”. All the blocks mine the same tanzanite deposit – which runs at approx 42 degree angle below them.

How durable is tanzanite?

Tanzanite has a similar hardness to an Emerald, but is less brittle. In order to preserve its beauty, simple precautions should be taken. It is ideally suited for wear in dress rings, earrings and necklaces. If you’re an active person, consider jewelry that won’t be exposed to as many bumps such as pendants or earrings. When cleaning tanzanite at the jewelry store, never allow them to clean the stone in an ultrasonic machine, which vibrates at high speeds – it its likely the stone will crack.

Is all tanzanite heated to turn blue ?

Zoisite forms reddish brown – and turns into blue when subjected to relatively low heat. However, this heating can occur naturally during tanzanite’s time in the ground, and some tanzanite does come out of ground already blue. The majority of tanzanite is gently heated after mining to remove the reddish brown color.

What color is the best?

Rich deep violet-blues and blue-violets are the rarest, and thus command a premium.Whether you choose a pastel or richer colored tanzanite is down to your preference and budget, but please be aware that tanzanite’s colorful brilliance intensifies in larger sizes – you’re generally not going find deeper colors in smaller sizes. ie 2.00 carats.

There is no price difference between a violet (bV) or blue (vB) dominant tanzanite. Purple tanzanite (not to be confused with violet tanzanite ) trades at a discount.

Tanzanite comes in a wide range of colors . The color often intensifies in larger sizes, with smaller sizes commonly occurring in pastel shades.

Does tanzanite come in any other colors like green and blue?

Tanzanite is the blue violet variety of the mineral zoisite. Rarely, zoisite is found in other colors, (often green’s, yellows, champagnes  – with pinks being the rarest). These colors are often called “fancy tanzanites”, although technically should be called ‘green zoisite’ rather than tanzanite. Sometimes these stones are called “ocean tanzanite, peacock or chameleon” tanzanite. Ocean tanzanite is rarer, but is traded at a lower prices than pure blue-violet tanzanite gemstones. Pink tanzanite is exceptionally rare, and trades at very high prices.

Green & blue, bi color, zoisite crystal. Blue-green zoisite is sometimes called “blue- green tanzanite” or “ocean tanzanite”. Photo Credit : Intercolor USA

Are there synthetics or imitations?

To date, tanzanite has not been created synthetically. The most common imitation is blue-violet glass. There was a period in the early 90’s when coated tanzanite was introduced into the market, however it is not commonly found today. Any company selling coated tanzanite is required to disclose the treatment by law.

Is tanzanite heat treated?

It should be assumed that all tanzanite is gently heated. However, it is not “heat treated” like many other gemstones,  laboratories like the GIA cannot test for heat treatment, and there is no effect on price. Excepting stones found close to the surface in the early days of the discovery, tanzanite is universally heat treated to produce a range of hues between bluish-violet to violetish-blue. This can occur naturally in the earth (from volcanic activity or wild fires), or through mild heating in the production process. This is considered a natural enhancement, which is permanent and stable. It is merely a continuation of what Mother Nature started. Since heat treatment is universal, it has no effect on price, and all finished gems are assumed to be heated. Green zoisite will not change color to blue if it is heated.