Jeweler Charles Hollander’s Royal Diamond Chess (shown in photo), priced at half a million dollars, is often cited as the world’s most expensive, but Hollander tells Bloomberg Businessweek that the first of his seven chess sets, which made their debut about 10 years ago, quietly sold for $600,000 just after launching. The set was studded with 320 carats of black and white diamonds and two kilograms of 14 carat white gold. Hollander says he presented the unnamed piece at the Basel Jewelry Show and sold it within the first hour to a Russian collector. Hollander has made seven luxury chess sets, all designed by Bernard Maquin, and has moved all but one. Another set, called the Jewel Royale chess set, by U.K. jeweler Boodles, was valued at $9.8 million but has not yet sold.

*No images of the set were taken before sale, according to Charles Hollander. The image shown is of the Royal Diamond Chess.