Asian collectors have long prized porcelain vases as much as paintings, but until recently, art lovers elsewhere largely treated ceramics like a second-class craft. Now, the global art market is trying to elevate clay art into the realm of the blue chip.

Christie’s and Phillips for the first time added stand-alone auctions of 20th-century and contemporary ceramics to their high-profile set of evening sales in London with examples by artists like Paul Gauguin, Lucio Fontana and Thomas Schütte. All but three of the 36 pieces...