Island Stone offers handcrafted Stone Mosaics Penny Rounds. The mesh-mounted 3/4-inch stone tiles come in three honed marble styles. Nebula ranges from light gray to rich, darker graphite tones with crystalline veining; Tempest features tones of charcoal to black with linear striations and natural patterning; and Carrara consists of shades of soft white with feathery gray veining.