Known for its glittery blue-violet color and its origins in the hills of East Africa, tanzanite may be one of the world’s most newly-discovered gemstones, but it has already achieved widespread popularity. From tanzanite’s unique characteristics, its discovery and history, and guidelines to purchasing tanzanite jewelry and stones, this guide covers everything you’ll want to know about this vibrant gemstone.
What Is Tanzanite?
Most people who are well-versed on gemstones identify tanzanite based on its rich blue-violet color. But what specifically about this gemstone makes it unique?
Tanzanite is a blue variety of the mineral zoisite and is made of calcium aluminum silicate. Its blue color comes from small amounts of vanadium within the zoisite mineral structure. Below is a chart with some of the stone’s most important properties.
Tanzanite Properties
| Chemical Composition | Ca2Al3(SiO4)3(OH) |
| Mohs Scale Hardness | 6.5 |
| Refractive Index | 1.69-1.70 |
| Luster | Vitreous |
Tanzanite’s average value of 6.5 on the Mohs scale means that it is not a particularly hard gemstone (by comparison, sapphire has a value of 9 and diamond 10). As such, tanzanite stones should be treated carefully to prevent damage.
Refractive index refers to how much light bends when it passes through the gemstone. Gems with a higher refractive index are more brilliant and appear to sparkle more. Tanzanite’s refractive index is slightly higher than average, although lower than the refractive index of some of the most popular gemstones such as diamonds, rubies, and sapphires.
Luster refers to how the gemstone looks when it reflects light. Tanzanite’s vitreous luster means it appears “glass-like”. Other gemstones that share this type of luster include quartz and topaz.
What Does Tanzanite Look Like?
Tanzanite comes in a variety of blues and purples, from pale to deeply saturated colors. Blue tanzanite is more common than purple tanzanite, although many stones have shades from both colors. The most desired color of tanzanite is a blue stone that includes shades of violet, and the more saturated a stone’s color, the more valuable it is.
Tanzanite stones are often heat treated to enhance or deepen their blue color. When tanzanite is heated, the oxidation state of the vanadium in the stone is changed, which results in a more vivid and attractive blue. Today, the majority of tanzanite stones being sold commercially have undergone heat treatment, and this treatment must always be disclosed by the seller.
Tanzanite is also pleochroic. Pleochroic gems show different colors when viewed from different crystallographic directions. Because of pleochroism, some tanzanite stones appear red when viewed from a certain angle.
Where Is Tanzanite Found?
One of the unique characteristics of tanzanite is that it’s only found in one place in the world: northern Tanzania, which is how the stone got its name.
As the story goes, in 1967, a local tailor and part-time gem hunter spotted vivid blue and purple crystals poking out of the ground in Merelani,Tanzania, near the base of Mt. Kilimanjaro. Thinking he’d discovered a vein or sapphires or peridot, two stones which look similar to tanzanite, he contacted a geologist and gemstone expert who, with the help of mineralogists in several locations, including Harvard University and the British Museum, identified it as a new mineral.
Today, tanzanite is found at multiple sites within a 20-square-mile area of Merelani and has not been discovered anywhere else.
A Brief History of Tanzanite
As mentioned above, Tanzanite was discovered in northern Tanzania in 1967. After it was determined to be a new type of gemstone, it was originally named blue zoisite.
Shortly after its discovery, the first of these stones were brought to New York, where they were examined by jewelers at Tiffany & Company. The jewelry company, recognizing the appeal of the gemstone’s vibrant color, quickly signed a deal to become the primary distributor. Concerned that blue zoisite sounded too close to “blue suicide” and would hurt sales, they changed the name to tanzanite.
Tiffany & Company soon began a large-scale advertising campaign to introduce tanzanite to customers and capitalize on its attractive color and exotic location of origin. Because the gemstone was so newly discovered, little was known about it, and the company had to produce education materials to introduce tanzanite to both jewelers and consumers. These materials explained where the gem was found, the colors it came in, and the qualities that made it unique.
The Tiffany advertising campaign helped create a surge of interest in tanzanite. Factors that contributed to the the gem’s popularity include its color, high clarity, and the potential for tanzanite stones to be cut in sizes larger than those typical of many other gems.
Today, tanzanite is still in high demand and is the second most popular blue gemstone (after sapphire). The stone is particularly popular in the United States, where approximately 75% of all tanzanite is sold.
Because the gem is found in such a limited location, there is concern that the supply of tanzanite will soon run out. Some people estimate that tanzanite stones will only be extracted for about 30 more years before the mines are emptied. While others contend that advanced mining techniques and the potential for new sources will keep supply going for much longer, tanzanite’s rarity has helped drive its popularity as many people want to purchase this striking blue stone while they still have a chance to do so.
Tanzanite Prices
Because tanzanite is found in such a limited location, it’s more subject to price fluctuations than most other gemstones. Decisions made by the Tanzanian government in regards to mining regulations and mineral rights have a significant and immediate impact on the price and availability of tanzanite. Additionally, since all tanzanite comes from a single source, natural disasters, such as flooding, can completely block access to the mines and sharply reduce supply for a time, causing prices to increase. This happened in 1998 when flooding in northern Tanzania caused tanzanite prices to skyrocket.
However, despite these price fluctuations, tanzanite remains consistently less expensive than sapphires of comparable quality, and thus is often purchased by people looking for a cheaper alternative to sapphire. Tanzanite stones are about a third the price of natural sapphire stones and roughly the same price as lab-created sapphires. It is often used as a substitute for the more expensive sapphire because both stones have a similar rich blue color. However, sapphires are less brittle and much harder than tanzanite stones, and therefore much more difficult to damage.
Prices for tanzanite vary widely depending on the size and quality of the stone. It generally costs between $700 and $1200 per carat for top-quality tanzanite. Tanzanite that has been set into jewelry will often be twice that price per carat.
It is possible, however, to purchase tanzanite at significantly cheaper prices than that, especially if the stone is imperfect or doesn’t have a deep color. Darker and more saturated stones are more expensive than lighter colored stones. A high-quality, two-carat tanzanite stone set into a ring with diamonds can cost $10,000 at Tiffany’s, but smaller and lower quality (but still gem quality) stones can be set in rings, earrings, or necklaces that cost just a few hundred dollars.
Tanzanite Jewelry
Because tanzanite has a low enough hardness (6.5 on the Mohr scale) to be damaged during regular wear, the gemstone is often set in earrings and necklace pendants, which subject the stone to less bumps and scrapes than rings and bracelets do.If tanzanite stones are set in rings or bracelets, it’s recommended that the jewelry only be worn on special occasions, rather than daily. The stones can also be put into specific settings that help protect them from damage.
Tanzanite stones can be cut into a wide range of shapes, but cushion, round and oval cuts are the most common because they highlight its rich blue color.
Because of its susceptibility to damage, tanzanite jewelry should never be washed in an ultra-sonic cleaner, which could scratch or crack the stone. Instead, a soft cloth and warm, soapy water should be used to clean the piece.
Interesting Facts About Tanzanite
- Because tanzanite has only been found in one location, the stone is actually 1,000 times rarer than diamond.
- Tanzanite is one of the birthstones for December and is also the gemstone traditionally given on 24th wedding anniversaries.
- Among the Maasai people, tanzanite is believed to represent new life and new beginnings. The stone is often given as a gift to celebrate births.
- The large blue stone in the “Heart of the Ocean” necklace Kate Winslet famously wore in Titanic was tanzanite.
- Some people believe wearing tanzanite jewelry lifts the wearer’s mood and removes negative habits. It’s also believed to enhance meditative skill.