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 rupiah made since coins were reintroduced to Indonesia in 1970 from either silver or gold. As commemorative coins, they were all sold above their intrinsic value, and also above their nominal value. All the coins struck are proof coinage, with the exception of the WWF 1974 coinage which were issued in non-proof 50% silver, and proof and non-proof gold. 36,000 gold pieces of the 1952 50 sen were minted that year, with the obverse design replaced with the Garuda Pancasila and text "INDONESIA" "BERKERDJA MENABUNG MEMBANGUN". With the exception of the WWF and Save the Children issues, which are in good