ForMatter/Finishes/cut/Cabochon (smooth dome)
finish_cut_cabochon

Cabochon (smooth dome)

cut · polished · cab, domed cut, non-faceted cut

An unfaceted gem — a polished dome over a flat or low-belly base. Used for opaque, translucent, and chatoyant stones (turquoise, opal, jade, cat's-eye chrysoberyl, star sapphires) where facets would be wasted. Reads soft, traditional, hand-shaped. The signet-ring stone, the Victorian mourning brooch.

Lapidary cabbing on a wheel — coarse grind to rough shape, fine grind to dome, pre-polish to remove scratches, polish on felt or hardwood lap with cerium-oxide or diamond paste. Dome height-to-base ratio typically 1:3 to 1:2. Optical phenomena cabochons unlock: chatoyancy (cat's-eye, in chrysoberyl), asterism (4-ray or 6-ray star, in corundum), play of color (in opal), aventurescence (in goldstone / sunstone). Faceting these stones would scatter the phenomenon out of view; cabochons concentrate it on the dome.

character — soft polished dome, hand-feel, color or phenomenon reads strongly.

Finish properties

  • levelpolished
  • subcategoryconvex polish
  • applies togemstone

Second life

reversibilityzero — gemstone facet styles are subtractive and committed once cut; "re-cutting" produces a smaller stone with different proportions. The original cut is permanent.
blocks substrate recyclingno
renewabilitymoderate — chips and edge wear can be re-polished with minor weight loss; major damage requires full re-cut to a new pattern.

GIA Diamond Grading and Identification literature; AGS American Gem Society cut-grading standards.