Some designs can be traced back to one touchstone, one key element that influences every other aspect of a room. This Woodbury living room, designed by CP Interiors’ Crystal Photiou, owes its colors and patterns to the green onyx fireplace surround. “The client said she’d been living in a house that looked like a college dorm and it was time to grow up.” After showing her the sample, the design took off. “The fabrics came from that green color, the rugs came from that and the furniture—it all built off the green onyx.”