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 Coins of the Indian rupee Coins of the Indian rupee were first minted in 1950. New coins have been produced annually since then and they make up a valuable aspect of the Indian currency system. Today, circulating coins exist in denominations of ₹1, ₹2, ₹5, and ₹10. All of these are produced by four mints located across India, in Kolkata, Mumbai, Hyderabad and Noida. After Indian independence, British Indian coins were in use as a frozen currency until India became a republic in 1950. The first rupee coins of the Republic of India were minted in 1950. These included 1/2