The process used is either minting or casting. Whereas minting is used for manufacture of small bars and coins in denominations up to 100Gm (mostly limited to 50Gm), the casting in a vacuum tunnel furnace is used for production of large bars. Obviously, the minting process is very time consuming and with low yield apart from high cost of manufacturing, the casting is the much-preferred process of manufacture of bars of 100gm, 500gm, and 1000gm.
Small minted bars beside carrying mandatory marking (stamping) on each side of the bar or coin, are also offered in temper proof packings to maintain its sanctity till it is used for further manufacturing. The cast bars of large denominations (100Gm and above) are embossed with markings such as purity and weight and a unique serial number to provide traceability to the refined metal from which it is manufactured.