Joel Arthur Rosenthal, aka JAR, makes around 100 jewels per year; clients often wait years to own one. So it came as no surprise when bidding wars ensued over four JAR originals at the May 13 Christie’s Magnificent Jewels sale in Geneva. This seductive sapphire, amethyst, and diamond ring made in 1988 shows off the designer’s phenomenal use of pavé. But its fresh color combination is JAR’s true hallmark. “In a very classic sense, you don’t mix a fine Burma sapphire with amethyst,” says Rahul Kadakia, Christie’s ­international head of jewelry. “Who does that? And yet he did it back in ’88!” Judging by the $784,500 hammer price, iconoclasm pays.