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 Indian rupee in 1964, which was a new denomination, and continued to be minted till 1971. One and Two paisa coins were changed to Aluminium and were minted without the Devanagari legend from 1965. 20 paisa coin was introduced in 1968, which continued to be minted till 1971. From 1982, New series was launched. the 20 paisa coin which was last minted in 1971, was reintroduced again, but in Aluminium. The size and the design of 10 paisa, 50 paisa and 1 rupee was changed, though they continued to be minted in the same metal. Coins of 3p, 2p and 1p were