VOCABULARY TERMS: RING TEST, DUMB BLANK

Ring Test. Tapping a suspended coin or medal on the edge for its resonance. The ring of any small metal object is due to its internal structure; thus its alloy, thickness and any gas pockets affects its tone. Both cast and struck items will ring but with notes of different pitch. It is necessary to compare a suspect item with a known or genuine item. Using a ring test for authentication, however, is delusive.

A ring test could detect a cast copy, for example, but could not differentiate a struck copy from an original. It could detect different metal compositions but not minute differences of alloy. The sounds of the ring test could range from a high prolonged tone (from a large thin piece) to a dull thud (from a thick base metal cast). A DUMB BLANK would fail a ring test by such a dull thud, as well as coins with a LAMINATION ERROR will fail the ring test.

A ring test is critical for gold coins. Concerned mints have employed testers to bounce freshly struck gold coins on a metal drum to check if they ring true. Dumb blank coins would be rejected and melted. The Philadelphia Mint did this, for example, until the early 1930s.
CLASS 11.2

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 is critical for gold coins; Breen states J.S. Ormsby $5 and $10 gold pieces were struck on dumb blanks because of poor refining.
CLASS 06.9

Reference:
NC10 {1988} Breen, p 634-635.

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