From sandblasting to polishing to general surface preparation, loose abrasives and media have a wide variety of applications for a wide variety of industries. Which media is right for your purposes will depend on several factors, including grit size, material hardness, friability, melting point, among others.
For more delicate surfaces, such as wood or softer stones, consider a media with less hardness and strength. Materials like Corn Cob and Walnut Shell will remove surface matter and refine delicate surfaces without pitting them or causing granular surface damage.
For stronger surfaces, like metal and denser stones, you may find a similarly strong media will suit you better. Consider Crushed Glass and Glass Beads for applications like paint removal and surface profiling, while even harder materials like Aluminum Oxide or Garnet for jobs that call for especially high-strength or abrasive media.