Obsidian (Gold Foil) is a semi-precious gemstone surface — a Black obsidian semi-precious gemstone surface composed of glossy broken stone segments joined by bold metallic gold-foil seams in a kintsugi-style mosaic. High-contrast, luxe decorative slab. slab with a polished finish, often backlit as a feature panel, vanity or bar front. A dramatic decorative stone for interior feature applications.