Tanzanite Guide

Gemstone color is often the most important factor in determining a gemstone’s value. Blue tanzanite is rarer and more highly valued than violet or purple tanzanite, but many people prefer stones with lighter violet hues. 

The cut of a gemstone is what gives it symmetry and shows off the stone’s color and brilliance. Because tanzanite is a pleochroic gem, the cut plays a significant part in which color takes prominence in the finished stone. 

Gemstone clarity is determined by any inclusions embedded in the gem, such as gas bubbles, fractures or small crystals. Most tanzanite gemstones have inclusions that are only visible with magnification—and any eye-visible inclusions typically cause a drop in price but don’t necessarily detract from the stone’s beauty. Inclusions aren’t always a bad thing! Rarely, tanzanite contains inclusions that create cat’s eye chatoyancy, a phenomenon where light reflects off the inclusions and produces a luminescent beam, similar to that of a cat’s eye. 

While diamonds are sized and valued by carat weight, gemstone size is based on diameter in millimeters. The size of tanzanite influences its color—large pieces of tanzanite have the finest color, but smaller gems are more abundant. 

Virtually all tanzanite on the market has been heat-treated to bring out the coveted blue to violet hues these gems are prized for. Heat treatments are a permanent, undetectable enhancement and don’t harm the gemstone, but rather add to its allure. 

LEARN ABOUT ENHANCEMENTS