Tanzanite buyer’s guide

Blue, violet, and the turn of the stone

Tanzanite shows different colors on different axes: blue, violet, and a brownish or pinkish direction. A good cut puts blue-violet through the table. Tilt the photo set. A stone that is only violet in one crop and brown in another is showing you its pleochroism, and you should see which color you will actually wear.

Deeper color is scarcer in larger sizes. A pale stone is not “bad tanzanite” if the price matches the color.

Wear

There is cleavage. A knock on a ring can split a stone that felt hard enough in the store. Earrings and pendants are safer. Do not use an ultrasonic cleaner. Do not leave it in a hot car.

It is not sapphire, even when the blue is beautiful. The species name is the durability warning.

Questions

Is unheated tanzanite common?

No. The blue-violet color of the trade is usually the result of heat. Unheated stones tend to stay brownish. If a listing says unheated, ask what supports that.

Is tanzanite a sapphire?

No. It is zoisite. Hardness, cleavage, and density are different, and so is the way the color shifts when you turn it.