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 quantities, using quite a bit of energy, to achieve significant gain.) In later years, the price of copper fell considerably. Copper plated steel coins were introduced to replace them. A circulating bimetallic two pound (£2) coin was introduced in 1998 (first minted in, and dated, 1997). There had previously been unimetallic commemorative £2 coins which did not normally circulate. This tendency to use the two pound coin for commemorative issues has continued since the introduction of the bimetallic coin, and a few of the older unimetallic coins have since entered circulation. There are also commemorative issues of crowns. Before 1990,