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 Czechoslovak koruna (1953) Coins of the Czechoslovak koruna (1953) After the 1953 currency reform a new series of coins were introduced. Coins were first issued in denominations of 1, 3, 5, 10, 25 h – the 1, 3 and 5 Kčs denominations only existed as paper money (state notes). The haler coins dated 1953 were all minted in Leningrad. The 1, 3 and 5 Kčs state notes were replaced by coins in 1957, 1965 and 1966, respectively. The 50 h coin appeared in 1963. In 1972 the 25 h and 3 Kčs coins were withdrawn, and – from 1972 – 20 h (as