Professional Jeweler Archive: The Supply and Demand Blues

May 2001

Gemstones & Pearls/News


The Supply and Demand Blues

Tanzanite prices are rising while sapphire's falls. In some cases they actually meet


Per-carat prices for East Africa’s tanzanite seem intent on climbing to the heights of Mount Kilimanjaro, in whose shadow the purplish-blue gems are mined. Blue sapphire prices, though, are trickling down to sea level.

The analogy doesn’t work across all categories. Top blue Kashmir sapphires command $11,000 per carat wholesale at the 3-5-ct. level. Nevertheless, just four years ago, a quality tanzanite topped out around $300 per carat. Today, the price can be twice as much for extremely fine tanzanites. And sapphires that sold for $1,000-$4,000 per carat wholesale four years ago can now cost as little as $450-$600.

The Tucson gem and mineral shows in February offered the opportunity for an experiment. Professional Jeweler borrowed two tanzanites and two sapphires to illustrate price similarities. Not only were the prices similar, so were their looks.

Supply and Demand

Tanzanite comes from only one commercial mine today, and it hasn’t produced much following cave-ins almost four years ago. As supplies fell, prices immediately shot up. “Tanzanite remains plentiful in lower qualities, says Stuart Robertson of The Guide, a pricing publication in Northbrook, IL. “Future supply of high-end material remains questionable though. We saw some top-quality tanzanite at the Tucson gem shows, but the prices were astronomical, in the $650 per-carat range.”

In contrast, Madagascar produces large amounts of sapphires in a variety of colors. “Six hundred dollars a carat will buy you a very decent Madagascar sapphire,” says Robertson.

Selling Blues

When selling tanzanite and sapphire, offer customers some background. Tanzanite has somewhat richer colors and saturations than sapphire. Even so, tanzanite tends to have a softer appearance because of its low dispersion. Tanzanite, a variety of transparent zoisite, is mostly purplish-blue. However, there also are rare cases of transparent green zoisite and pink zoisite (which some call green tanzanite or pink tanzanite). These are considered collector gems.

Sapphires, meanwhile, are much more durable than tanzanite and can be worn every day without as much concern for their longevity. Sapphire tends to take a more brilliant polish than tanzanite and invariably has greater dispersion, though some included sapphires can have a soft appearance as well. A variety of corundum, sapphire comes in many colors, though blue is the most likely to compete with tanzanite.

Because tanzanite and sapphire prices have begun to overlap, some consumers may take tanzanite more seriously. You can help the process by taking time to explain the similarities and differences between the two gems so your customers can make an informed choice.

– by Robert Weldon, G.G.


The tanzanites are courtesy of Gemtech International Corp., New York City; (800) 436-3236. The sapphires are courtesy of John M. Bachman Inc., Boulder, CO; (303) 440-4474.

Photo by Robert Weldon.

Copyright © 2001 by Bond Communications