Tanzanite Buying Guide - What factors to look out for when browsing

Color

As with all colored gemstones, it is the color of the Tanzanite that determines the value. Tanzanites tend to be either mostly blue or mostly violet and while personal preference plays a part, the bluer gemstones are the most sought after and, therefore, the most expensive.

Deeply saturated blue violet or violet blue colors are deemed the most attractive but lighter pastel shades also have plenty of admirers and can be found at slightly lower prices.

Many tanzanite gemstones display two or three different colors when viewed from different angles. Again, a dominant blue color with violet, purple or even red flashes is the favorite.

Clarity

Most tanzanite gemstones worthy of being used in jewelry will be what we call 'eye-clean', that is any blemishes or inclusions can only be seen under magnification not the naked eye. There is no need to settle for anything less. Any fractures or cracks will lower the value considerably.

Some translucent or even opaque tanzanite gemstones can be found as cabochons – rounded shapes with flat bottoms – that can make interesting looking jewelry items or attract the eye of a collector as they are significantly less expensive than faceted gems.

Carat

Tanzanite gemstones come in all sizes from tiny stones just a few millimeters in diameter to be used as side stones or channel and pave settings all the way up to magnificent gems of 10 carats or more.

The larger stones are, of course, much rarer and can command a considerable price – gemstones of more than 3 carats are three or four times the price per carat than smaller examples.

The size can affect the look of a gemstone immensely as a nice deep stone can mean excellent color saturation that cannot really be achieved with smaller tanzanites.

Cut / Shape

Even the best colored gemstone can be spoiled by poor quality cutting and this is perhaps more true for tanzanites than most other stones. Tanzanites change color when viewed from different angles and since blue is the preferred dominant color, cutters will try to ensure the stone is blue when looked at from the top and violet from the side.

Boosting the blue color is more difficult and if you cut the stone incorrectly it will appear more violet from the top and therefore be less valuable.

In addition, the gemstone needs to be cut and shaped to maximize the natural fire and scintillation of tanzanites – poorly cut stones will appear dull and lifeless. Oval, pear, round and cushion cuts are always popular and can really show off the tanzanite's outstanding qualities.

Jewelry

Tanzanite is rated at around 6.5 - 7 on the Mohs hardness scale so is quite low when compared to sapphires and rubies but is still good for most types of jewelry although exposed ring settings could be subject to chipping or cracking.

With the variety of sizes available, tanzanite is ideal for jewelry sets as large singles, matching pairs and small lots in identical shapes and color are relatively easily obtained.

Treatments

One of the stories surrounding the discovery of tanzanite in the hills of northern Tanzania near the majestic Mt Kilimanjaro tells of Maasai herdsmen tending their cattle not long after a grassland fire. The heat of the fire had caused the normally brown rocks that littered the fields to glow an intense blue.

This may just be a myth but virtually all tanzanite gemstones are heat treated these days to achieve the stunning blue to violet coloring.

Price

As a rare and beautiful gemstone, tanzanite can command a premium price based on the various criteria such as color, clarity, cut and carat size that we have mentioned. As an expensive gemstone we recommend only purchasing from a reputable dealer with an excellent return policy and to get the gemstone properly and independently certified.

Birthstone

Tanzanite is one of the birthstones for December.

Wedding Gemstone

Tanzanite is the traditional wedding gift for the 24th anniversary.

Durability

Tanzanite is rated 6.5 – 7 on Mohs Hardness Scale