Found in just one place on earth, tanzanite is a relatively recent discovery. Tiffany & Co named this blue-violet variety of zoisite in honor of Tanzania, where it was first unearthed in 1967. Because the crystals show different colors depending on the viewing direction, cutters can fashion gems with a range of color from violetish blue to bluish violet depending on how much weight they want to retain from the rough.
Birthstones & AnniversariesTanzanite is a birthstone for December, along with zircon, turquoise, and blue topaz. Tanzanite is also the gem for a 24th anniversary.
Tanzanite has only one source: the hills of Merelani in northern Tanzania.
Masai tribesman Ali Juuyawatu is credited with finding the first tanzanite crystal.
Tilt tanzanite and you’ll see three distinct colors in three crystal directions.
Violet blue to bluish violet to violet purple
1.691 to 1.700
0.008 to 0.013
- Mohs Hardness: 6 to 7
There are a number of processes used to alter the color, apparent clarity, or improve the durability of gems.Learn More
Some gemstones have synthetic counterparts that have essentially the same chemical, physical, and optical properties, but are grown by man in a laboratory.Learn More
Any gem can be imitated—sometimes by manmade materials or by natural materials chosen by man to impersonate a particular gem.Learn More
Why We Love This Gemstone
Tanzanite is pleochroic, showing three different colors when viewed from different directions.
One Place on Earth
Commercially mined in only one place, tanzanite is rarer than diamond.
Tanzanite's rich blue-to-violet hues can be exceptionally beautiful.
Assessment of the following characteristics determines tanzanite’s value.
Deep saturated violet blue or blue violet are the most valuable tanzanite colors. Paler hues are more commonly found.
Eye-visible inclusions decrease the value of tanzanite, particularly in lighter colored stones.
Tanzanite is available in a wide range of shapes but cushion and oval cuts are most common.
Tanzanite color is less saturated in smaller sizes. Gems must be above five carats in size to have fine color.
Tanzanite Quality Factors: The Comprehensive Guide
Explore sources, gemological research, and the role of gems in history.
Gem Wealth of TanzaniaDona M. Dirlam, Elise B. Misiorowski, Rosemary Tozer, Karen B. Stark and Allen M. Bassett , Jun 1, 1992 Read Article
Emerald & Tanzanite Buying Guide
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