Covington buff & polish chart


This comes from the Covington Catalog

  1. Many stones polish equally well with several buff and polishing compound combinations. A very hard gem can be polished by a much softer polish powder. Only one polishing agent should be used on a buff.
  2. Polishing does not remove any material from the surface. If scratches develop, the stone must be re-sanded.
  3. It is impossible to obtain a high glossy finish on very soft materials, especially if they tend to be slightly porous, fibrous or granular. As a last resort with this type of material, a finish gloss can be given by the use of spray varnish.
buff polishing compound
material canvas phenolic felt leather muslin cerium oxide chrome oxide diamond linde "a" tin oxide
agate c a b a-b c
amethyst c a b a-b c
beryl d a b-c a c d b
calcite b a a-b
chloastrolite a a
feldspar a a
garnet c a-b b a c
glass a
goldstone a b
hematite b a a b a
howlite a b a c
jadeite a-b c b b
jasper a b a a
lapis lazuli a-b b a
malachite a-b b a
nephrite-jade a-b c b c
obsidian a a
opal-australian a b a b
opal-mexican a a
psilomelane a-b a b
petosky stone a a
quartz c a b a-b c
rhodochrosite a-b a b
rhodonite a-b b a
serpentine a-b a b
sodalite a a
thomsonite a a
tigers eye a a
tourmaline c a-b b c a
turquoise a-b a b
unakite a a
variscite b-c a b a c
wonderstone b-c a a c
Match letters across rows for best combinations


  • Canvas: Canvas is useful when polishing heat-sensitive stones because it develops very little friction.
  • Muslin: Muslin buffs are recommended for soft stones and gems that are heat sensitive.
  • Leather: Leather is a versatile buffing material that is both efficient and economical. Leather generates heat, but not as much as felt.
  • Felt: Felt is useful for polishing glass and stones of even texture. It is not recommended for gemstones that under cut. Friction on felt generates heat.
  • Phenolic: Phenolic tools or phenolic lap disc (cab laps) are useful when impregnated with diamond grit.14,000 Micron (pre-polish) or 50,000 Micron (polish) diamond compound can be applied to the surface of the gemstone and worked with a phenolic carving tool. It can also be applied to the surface of a phenolic lap disc and worked with the gemstone mounted at the end of a dop stick. The diamond will charge the phenolic plate making smoothing and polishing easier.


  • Cerium Oxide: Covington cerium oxide will polish at a faster rate than conventional polishing compounds and produce a superior optical lens surface with no staining or caking. Because it will polish faster, a lower concentration can be used. It is recommended for use on leather, felt, polyurethane foams, and thermoplastic polishing pads. It is a favored polish for quartz type minerals and other gemstone types. It is not recommended for gemstones that will under cut.
  • Linde "A": A .3 micron aluminum powder that is carefully graded for uniformity of grain size. It is excellent for polishing stones that will under cut. Excellent for hard to polish stones.
  • Chromium Oxide: Chromium oxide is a hard polishing agent. It is green in color and stains badly. It is useful for polishing jade and stones that will under cut.
  • Tin Oxide: Tin oxide is an excellent general-purpose polish. It is used to provide a final high gloss finish.
  • Diamond: Diamond grit is the most efficient polishing medium. It is especially useful for polishing difficult-to-polish stones.
Did you find what you were looking for?