Colorful Agate (Backlit) is a semi-precious gemstone surface — a Backlit semi-precious agate slab — a mosaic of many individual polished agate slices set in dark grout, each showing concentric agate banding. Vivid multicolour, illuminated from behind for a stained-glass ​/​ gemstone effect. A decorative feature surface. slab with a polished finish, often backlit as a feature panel, vanity or bar front. A dramatic decorative stone for interior feature applications.