Tanzanite is like all other gems in that small stones are more abundant than larger stones. Most faceted tanzanites are under five carats in weight. Stones over fifty carats are very rare.

Small stones are typically cut into calibrated sizes for use in commercial jewelry. Those with top-grade color are the most valuable and often go into custom or designer jewelry.

Large stones with exceptional color are very rare. These are often purchased by collectors, museums, or investors. Some are also used to make special pieces of custom or designer jewelry.

The size of a tanzanite gem influences its color. If you have two stones of equal saturation, the larger stone will have a richer apparent color – because the distance that light travels through the stone has an influence on its perceived color.

Tanzanite gem: A violet-blue tanzanite measuring 7 x 5 x 3 millimeters in size and weighing 1.02 carats, antique facet cut. This grade of tanzanite is often seen in mall and chain store jewelry. The stone in the photo at the top of this page might be seen in exclusive jewelry stores or in showings of designer or custom jewelry items.