Whilst one large Anglo-Saxon silver penny and one much smaller Charles I silver penny both have the same nominal value (one penny) and are both made of the same material (silver), because the Anglo-Saxon coin is much larger and contains far more silver it has a higher commodity value – showing how a nominal value and commodity value can differ.

The accurate value and quality of coins produced by The Royal Mint is determined through the Trial of the Pyx. Here we explore how coins are tested, and the role the Trial plays in ensuring The Royal Mint maintains the highest level of quality when producing the nation’s coinage.

The Trial of the Pyx is a procedure which has taken place since 1282 and is an annual judicial ceremony to test and ensure that The Royal Mint’s newly minted coins meet the required standards.

The Trial is held every February and is judged by a jury of over six assayers from the Company of Goldsmiths, who are independent from The Royal Mint. After the coins have been inspected and judged for their weight, diameter, and composition, the verdict is then read aloud by the Clerk of the Goldsmiths’ Company at the instruction of the Senior Master and Queen’s Remembrancer – an ancient post created in 1154 by Henry II, and the oldest judicial position still in existence.

This verdict is received by the Chancellor of the Exchequer under their capacity of Master of the Mint. In the past, if the coinage is found to be substandard, the trial carried a variety of punishments for the Master of the Mint, including a fine, removal from office, or imprisonment. However, these do not happen today.

Isaac Newton and the 1710 Trial

One of the most famous, and most controversial, examples surrounding the inaccurate value of coins comes from the 1710 Trial of the Pyx, where Isaac Newton’s coins were found to not contain enough gold.

In 1696, Sir Isaac Newton moved from his post at Cambridge University to London to first become the Warden of The Royal Mint, and three years later, the Master of the Mint.

The role of Master of the Mint had traditionally been a ceremonial one, however, Newton wanted to make a contribution. He encouraged the engravers to up-skill themselves by taking on outside work, increasing the quality of their coins which also made them more difficult to counterfeit. Newton also started fastidiously pursuing counterfeiters through the courts which resulted in The Royal Mint gaining the reputation of one of the most trustworthy and accurate Mints in the world.

Therefore, when Newtons coins were judged as being below the required standard and not containing enough gold in the 1710 Trial of the Pyx, Newton reacted angrily, and set about proving the judgement procedure as faulty.

The coins in question had been compared with a new gold Trial of the Pyx Plate, introduced in 1707, and Newton managed to prove that it was in fact the plate that contained too much gold, and therefore his coins were not below the required standard. As a result, the earlier trial plate of 1688 was returned to use.