Definizione

• Dumb Blank.  A planchet which fails a ring test (because of trapped gas, cracks or other imperfections in the metal). A piece struck from a dumb blank would still fail a similar ring test. Testing for dumb blanks are critical for gold coins; Breen states J.S. Ormsby $5 and $10 gold pieces were struck on dumb blanks because of poor refining.
  Reference:                                                                                                                              
  NC10 {1988} Breen, p 634-635.

  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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