Definição

• Burnishing.  A smoothing and brightening of a metallic surface by contact and rubbing with a stone or metal burnisher. Burnishing adds luster to a smooth surface and will remove the slight traces left by chasing (or other tool marks), from polishing with emery or other polishing materials. The form of the burnisher is immaterial and can take many forms, the only requirement is that the burnisher be a harder substance than the metal being burnished; it is, of course, very smooth and polished.
  Burnishing is done by hand, often after chasing; or burnishing can be mechanical, as in a tumbler (see tumbling). Burnishing gives gold a highly reflective surface, silver a black luster and bronze a medium reflective surface.
  Plated items may require burnishing on smooth areas, as the fields; the burnishing actually works plated crystals into the base metal surface irregularities and effects a harder surface in addition to a smoother one.
  Burnishing on a coin is done to remove a rough surface area; it is not an approved technique, however, as the area may be a characteristic of a particular variety. Some modern mint prducts are advertised as having a “burnished” surface, but this is a misnomer invented by overactive marketing personnel. Normal coins are never burnished or chased. In the medallic field burnishing is used in chasing, finish and finishing. See also reflectiveness.

  excerpted with permission from

  An Encyclopedia of Coin and Medal Technology

  For Artists, Makers, Collectors and Curators

  COMPILED AND WRITTEN BY D. WAYNE JOHNSON

  Roger W. Burdette, Editor

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