AUBURN – All that glitters is not gold.

Sometimes it’s tanzanite.

A collection of the precious gemstone from East Africa – including a set valued at $1 million – will be on display in the jewelry department of J.C. Penney Aug. 25. The collection, designed by jeweler Eddie Le Vian, is making a national tour. Auburn is the only stop in Maine; the show will appear at eight other locations around the country.

“It’s really a neat thing for the area,” said Kelly Caringi, jewelry department manager. “This is the largest tanzanite show in the world.”

Auburn was selected in part because shoppers have already proved their appreciation for the purple-blue gem. Last year, Caringi said, her department sold about $50,000 worth of tanzanite jewelry.

“It’s become very popular,” she said.

The collection will feature 600 to 1,000 pieces of tanzanite jewelry in platinum and 14- and 18-karat gold settings, as well as some loose stones. Prices range from $99 to the $1 million set. Caringi said Le Vian’s company expects to make at least $10,000 from the show.

Extra security will be hired by the retailer; the collection has its own security as well.

Caringi encouraged shoppers to call for appointments if they want personal attention during the show, but all are welcome to see the collection. It will be on display from 9 a.m. to 9 p.m.

According to the International Gem Society, tanzanite was discovered in the 1960s in a small area of Tanzania. Heavy rains caused cave-ins at some of the mines and they were closed in 1998, shrinking the supply of tanzanite. Prices vary widely, but before the mines closed, top-quality tanzanite could be found for $100 per carat; now it’s closer to $1,000.

The gems are mostly brown when they’re mined, but are heated to 700 degrees Celsius, which causes the blue-purple color to appear.

“They are bluer than an amethyst and much more vibrant,” said Caringi. “They’re a fairly new gemstone but quite desirable.”

Caringi developed a good rapport with the agents for tanzanite jewelry because of the brisk business the Auburn store was doing. That relationship also helped bring the show here.

“Normally these kinds of jewelry shows don’t even come to Maine, never mind this area,” she said. “It’s really great for us.”