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 New Zealand dollar Queen. Towards the end of the 1980s, the 1c and 2c were becoming of little value, and it was decided to withdraw these coins from circulation. The last coins of these denominations were minted for circulation in 1987, with collector coins being made for 1988. The coins were slowly withdrawn from circulation, before finally being demonetised (no longer legal tender) on 1 May 1990. After the withdrawal of these coins, cash transactions were normally rounded to the nearest 5 cents, a process known as Swedish rounding. Some larger retailers (notably one supermarket chain), in the interests of public relations, elected