Darren Henault has made customization a calling card. “We rarely do something ‘off the shelf,’ ” says the designer, who has offices in Manhattan and Millbrook, N.Y. “Most of the clients I have want something unusual. Or something that’s completely unique to them and their home.”

Bespoke and rare surfaces and finishes have become a coveted must. Why keep up with the Joneses when you can turn their heads? “High-end design is no longer about abundance but about distinction,” adds Lisa McDennon, a designer in Laguna Beach, Calif.

Just as Mughal emperor Shah Jahan willed the semiprecious-stone inlay of the Taj Mahal into being, a certain clientele doesn’t just expect the unexpected but commands it. Today, that can mean a stair railing sculpted from cast bronze or a chandelier made of 450 shards of selenite (both, by the way, are Henault commissions). Here are the surfaces coveted by the design cognoscenti now.