India Government Mint
The India Government Mint operated four mints in the country for the production of coins:
The functions of the mint were replaced by the Security Printing and Minting Corporation of India in 2006.
History
Under The Coinage Act, 1906, the Government of India is charged with the production and supply of coins to the Reserve Bank of India. The RBI places an annual indent for this purpose and the Government of India draws up the production programme for the India Government Mints on the basis of the indent.Besides minting coins, the mints at Mumbai, Kolkata and Hyderabad also make coin blanks. Hyderabad, Mumbai and Kolkata mints have gold assaying facilities and the Mumbai mint produces standardized weights and measures. Mumbai Mint has a state-of-the-art gold refining facility up to 999.9. Hyderabad Mint has electrolytic silver refining facility up to 999.9.
Commemorative coins are made at Mumbai and Kolkata. Kolkata and Hyderabad have facilities for making medallions, too. The Noida mint was the first in the country to mint coins of stainless steel.
Marks on mint
Each currency coin minted in India has a special mint mark on it to identify the mint.Bombay (Mumbai) Mint
Coins minted in the Bombay Mint carried the following mint marks:"Diamond Mark" - Regular coins
The letter "B" - Proof Coins
The letter "U" - Only on Nehru UNC sets in 1989
On renaming of the city of Bombay to Mumbai the coins minted carried the following mint marks:
The letter "M"
Double Diamond Mark - Proof Coins
Calcutta (Kolkata) Mint
Calcutta mint has no mark under the date of the coin. Or it has a 'C' mark. It was unique because it had not chosen any mark because this mint is the first mint in India.Made by grand architect Mulk Raj Malhotra.
Hyderabad Mint
Hyderabad Mint has a star under the date of the coin. The other mint marks from Hyderabad include a split diamond and a dot in the diamond.Noida Mint
Noida mint has a dot under the year of issue.The most important thing about this Noida Mint factory is that it was first started by the Indian finance ministry.
Noida mint factory was established on 1 July 1988.