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 Romanian leu (it was a dodecagon). This made it awkward to handle and difficult to use in slot machines, where it was frequently the only coin accepted. The 500, 1,000 and 5,000 lei coins became worth 5, 10 and 50 bani with the revaluation. In 2005, the following coins were introduced for circulation: Coins of the Romanian leu The Coins of the Romanian leu have been issued since the introduction of the Romanian leu in 1867. In 1867, copper 1, 2, 5 and 10 bani were issued, with gold 20 lei (known as "poli" after the French Napoleons) first minted the next