Metallurgical assay and the U.S. Mint continue to produce precious metal bullion coins for collectors and investors. The precious metal purity and content of these coins is guaranteed by the respective mint or government, and, therefore, the assay of the raw materials and finished coins is an important quality control. In the UK, the Trial of the Pyx is a ceremonial procedure for ensuring that newly minted coins conform to required standards. Metallurgical assay A metallurgical assay is a compositional analysis of an ore, metal, or alloy. Some assay methods are suitable for raw materials; others are more appropriate for finished goods.
Coins of the pound sterling but normally did not circulate. All modern coins feature a profile of the current monarch's head. The direction in which they face changes with each successive monarch, a pattern that began with the Stuarts. For the Tudors and pre-Restoration Stuarts, both left and right-facing portrait images were minted within the reign of a single monarch. In the Middle Ages, portrait images tended to be full face. From a very early date, British coins have been inscribed with the name of the ruler of the kingdom in which they were produced, and a longer or shorter title, always in Latin; among