Obsidian (Silver Foil) is a semi-precious gemstone surface — a Deep jet-black obsidian gemstone slab fractured into large angular fragments, with a bright silver-foil vein network filling the cracks in a crazed, web-like pattern. Bold, high-contrast luxury look. slab with a polished finish, often backlit as a feature panel, vanity or bar front. A dramatic decorative stone for interior feature applications.