Trial plate

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.^[1] 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.^[2] 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.^[3]