Via the NewYork Times:

… At the Evolution Store, the designers admired a large chunk of polished petrified wood — part of an ancient tree that had fossilized to stone — noting that it would make an appealing (if heavy) stool.

As Mr. Buntain said, “It’s a nice object because it’s quiet but has an incredible history.” And its coloring, he added, made it look “almost like bone or horn.”

For those in search of something even more primitive-looking, the pair suggested the Delaware Bluestone chair by Max Lamb at Johnson Trading Gallery. “It’s just a raw piece of stone,” Mr. Buntain said. “But through the simple process of cutting away, he’s created this beautiful, functional, sculptural product.”