trial piece Público Deposited
Any OMS in baser metal than the intended coin. Typically, trial pieces of copper coins are in brass, tin, "white metal," or lead; trial pieces of silver or gold coins are in any of the above or in copper. Between about 1863 and 1885, U.S. proof sets were struck from regular dies in copper, nickel, and aluminum; these are commonly classed as trial pieces, though a more accurate designation is pieces de caprice.
- Breen Encyclopedia