Inlay and decorative materials are the small additions that take a pour from ordinary to one-of-a-kind. Crushed stone, metal flake, glow-in-the-dark powders, copper and brass shavings, mother-of-pearl chips, and dozens of other small materials you can suspend in resin or use as inlay accents on wood or hybrid pieces. Once you start casting your own blanks, this is the category that funds the addiction — there's always a new material to try.