A
Trial plate was a piece of metal used as a standard in the
assaying of coins to determine a coin's accuracy and
fineness. Plates made from various metals including
copper,
silver and
gold were used in events such as the Trial of the Pyx as benchmarks of quality.
A contender for the earliest known ingot-shaped silver trial plate that dates from 1279 and is held by the Royal Mint Museum in the
United Kingdom.
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