LVMH, owner of natural diamond jeweler Tiffany & Co., has begun showing clients watches and jewelry featuring lab grown diamonds, testing luxury buyers interest in using man-made stones at the very top end of the market.

In private appointments with clients at its Paris flagship on Rue de la Paix in recent weeks, LVMH's Fred label has been showing a new high-end jewelry set built around lab-grown diamonds in an unusual blue hue - meant to evoke the sea and reflect founder's nautical roots - surrounding them with natural, white diamonds.

One of the pieces, a 240,000 euro ($255,000) necklace, features the blue synthetic diamond in half a carat, a color that took years of research to develop, according to the label.

On Tuesday, when asked if LVMH could broaden its use of artificial stones at Tiffany, finance chief Jean-Jacques Guiony said: "Is it a long-term trend that we could develop elsewhere? It's too early to say," noting that the group's bets on man-made stones must be "weighed and assessed carefully."

Within the sprawling luxury empire, Tag Heuer CEO Frederic Arnault, one of five LVMH heirs, made the first moves to use lab-grown diamonds, incorporating them in some of the brand's priciest watches, including a $90,000 timepiece with a 1.3-carat pink lab-grown diamond as the crown, unveiled earlier this year.

The use of man-made diamonds in luxury products comes as LVMH remains focused on marketing natural diamonds, particularly at Tiffany, where efforts are led by Frederic Arnault's older brother, Alexandre Arnault, head of product and marketing.

The label, which is pushing into China, emphasizes the provenance of the American jeweler's diamonds which are sourced from countries such as Australia, Botswana, Namibia, South Africa and Canada.

Lab-grown diamonds have become more accepted in the United States, where cheaper brands like Pandora and Signet have been increasing their offers of artificial stones.

($1 = 0.9420 euros)