Gem News International Gems & Gemology, Spring 2019, Vol. 55, No. 1

Unusual Faceted Gemstones


173.22 ct pink fluorite from Switzerland.
Figure 1. A pink 173.22 ct fluorite, measuring 35 × 33 mm, from Uri, Switzerland. This stone is representative of minerals discovered by strahlers, mineral hunters from the Swiss Alps. Photo by Kevin Schumacher, courtesy of Gravier & Gemmes.

Denis Gravier of Gravier & Gemmes (Poncin, France) exclusively sells rare and unusual faceted stones, such as the pink fluorite from Switzerland shown in figure 1. During the GJX show, he shared insights about the market for such gems.

Gravier developed a passion for colored stones and minerals while growing up in the French countryside. He studied mineralogy, crystallography, and petrology before traveling to the Republic of the Congo, Pakistan, Mexico, the former Yugoslavia, and Morocco a few decades ago to collect mineral specimens. He also learned gemstone cutting techniques. With the knowledge and experience he gained, he decided to open a company specializing in faceted stones of unusual varieties. Some of these gems, he explained, are rarely if ever used in jewelry. The challenge is finding them, but after decades of traveling and visiting the mines, he knows many people in the trade. Now the stones come to him during major shows, so it is no longer necessary to go to the sources. He still travels occasionally to Sri Lanka and Madagascar, where he buys rough that he will have cut in France or overseas. Gravier says Tucson “is a great show…you can almost see all that is available in the world at that time during the show.” In Tucson he meets with clients from the U.S., Japan and other parts of Asia, and European countries.

In terms of novelty and rarity, Madagascar offers the largest variety and supply. New gemstones are always emerging, Gravier explained. Among his stones from Madagascar were the dumortierite and green sphene in figure 2.

Dumortierite and sphene from Madagascar.
Figure 2. Unusual stones from Madagascar. Left: A 0.51 ct dumortierite (5.4 × 4.5 mm). This mineral, commonly known as an inclusion, is now available in very limited quantities as a gem. Right: A 19.65 ct round-cut green sphene. Photos by Kevin Schumacher, courtesy of Gravier & Gemmes.
1.21 ct intense yellow legrandite.
Figure 3. A 1.21 ct intense yellow legrandite, a rare zinc arsenate mineral from Mexico. Since the last discovery of this mineral in the 1970s, it has appeared on the market only sporadically. Photo by Kevin Schumacher, courtesy of Gravier & Gemmes.

He also described the market for unusual faceted gems. Collectors, not the jewelry industry, are the clientele for rare stones in France and around Europe, which is dominated by the “Big Three” and diamond. Faceted legrandite (figure 3), grandidierite, and dumortierite, for example, are generally not used in jewelry pieces. On the other hand, in Asia, especially Japan, people are attracted by rarity and there is a demand for “exotic” quality material, even in small sizes, for use in jewelry. Gravier feels that more people there have a general knowledge of and interest in gemology and colored stones. The Chinese market is becoming increasingly important for his business. One benefit of the rare stone market is that treatments are not common among these gems, making it a good source for people seeking untreated material.

Even though there is growing competition, with goods at all price points available on the Internet and aggressive marketing through the web and social media activity, Gravier chooses not to sell on the Internet. He invests in improving the quality and variety of his stock, relying on his long-term relationships with clients and suppliers.

Gravier sees a rising interest in rare stones. He believes he is helping to create more appreciation for a wide range of colored stone varieties. He hunts for rare treasures and, as an ambassador for unusual stones, gives them a chance for public exposure and recognition.

Unusual Faceted Gemstones

Jonathan Muyal is a staff gemologist at GIA in Carlsbad, California.