India got independance on August 15th 1947. From 1947 to 1950, the Government of India continued the earlier coins of the British India. And the coins of 1947 were minted upto 1950 by the Government. India became a Republic on 26th January 1950.
In 1949, the Government Mint produced 14 types of pattern proof coins made of Nickel, Cupro-Nickel Alloy or Brass. However, the Krause mentions the Nickel and Cupro-Nickel coins only. Their mintage was very few and each of them is valued at around 600 Dollars. And more than that, you should be fortunate to buy one such coin. I saw one of those coins from the site of 'coinvault'. So, without hesitation, I bought it. I tried to know more about these coins. But it seems there is almost no one who is interested in these coins out here. So, if you know any information about these pattern proof coins from the Republic India, please let me know.
On 15th August 1950, the Government of India started minting their own coins. Then onwards, the obverse of all the Indian coins show the 'lion capital' taken from the Asoka Pillar. The pillar was made by the mighty Asoka the Great (272 BC - 236 BC) who later embraced Budhism and preached 'ahimsa' which means 'no killing'. In 1950, the Government issued 1 Pice, 1/2 Anna, 1 Anna, 2 Annas, 1/4 Rupee, 1/2 Rupee and 1 Rupee coin for circulation. 16 Pice was equal to 1 Anna and 16 Annas were equal to 1 Rupee. All these coins have sharper finish than the later coins. So, these coins are in great demand. Also, some of these coins are slightly different compared to other issues, especially the 1 Pice, 1/2 Anna, 1 Anna and the 1 Rupee coins. This series, famously known as the 'Anna Series' prevailed upto 1957.
In 1957, the Decimal Coinage was introduced. The One Rupee coin remained the same. All the others were changed. One Rupee became equal to 100 Paise. The denomination introduced were 1 Naya Paisa, 2 Naya Paise, 3 Naya Paisa, 5 Naya Paisa, 10 Naya Paisa, 25 Naya Paisa and 50 Naya Paisa. The word 'Naya' was meant to make the people familiarise with the new coins. 'Naya' means 'new'. This word was dropped after 1964.
Mint Marks : It is difficult to determine the mints of Indian Republic coins for a novice. You will need a good magnifying glass. Also, the coins should be atleast in the grade of 'very fine'. In some cases, even the 'very fine' condition wont be enough. The reason is that, generally, the circulating coins from India are not sharper as compared to the coins from other countries (so I feel). The mint marks usually appear right below the date. The most common mint marks are No mint mark (Calcutta), Diamond (Bombay or Mumbai), Star (Hyderabad) and Dot (Noida). It is particularly difficult to differenciate between a dot and diamond mint mark. You will need the help of a magnifying glass sometimes. Also, care should be taken to determine whether a coin belongs to Calcutta Mint or not. Because, due to wear and tear, sometimes the mint marks may not be visible. The 'not that common' mint marks are : B (Bombay or Mumbai), C (Ottawa), H (Birmingham), Diamond split vertically (Hyderabad), Dot in Diamond (Hyderabad), 'MK' in circle (Kremnica, Slovakia), Diamond below the first digit of the date (London), M (Mumbai or Bombay), M beneath O (Mexico), M in oval (Pretoria) and Star below first date digit (Taegu, Korea).
Some Interesting Facts
From 1950 to 1968, the One Rupee coins were issued only in 4 years (1950, 1954, 1962, 1964). Each of them is recognised as a type by Krause. From 1969, the One Rupee is issued every year. However, the One Rupee coins for the years 1971, 1972, 1973 and 1974 are found only with the proof sets.
There are 3 recognised mule coins from the Republic of India. One is the 10 Paise coin issued in 1979 to commemorate 'International Year of the Child'. The mule coins has the obverse of the 1978 Ten Paise coin commemorating 'Food and Work for All'. Second is the 50 Paise issued in 1985 to commemorate the death of Indira Gandhi. The mule coin has the obverse of the 50 Paise coin commemorating 'Fisheries' also minted in 1985. The third is the 50 Paise 'Fisheries' 1985. The mule has the obverse of the 50 Paise Indira Gandhi 1985 coin. The rarest of the three mules is the 'Fisheries' mule. The obverse of a common Indira Gandhi 50 Paise and Fisheries 50 Paise can be easily distinguished by the presence of a line made of dots on the rim of the Indira Gandhi coin. The obverse of 'Fisheries 50 Paise' has no such lining.
There is only one Piefort (coins which has twice the weight of a common coin) issued by the Reserve Bank of India. That is the 100 Rupees Piefort issued in 1981 to commemorate 'International Year of the Child'. This coin is 58.320 grams of 0.925 silver.
The 2 Rupee coin issued in 1985 to commemorate the Golden Jubilee of Reserve Bank of India can be found only in the Proof sets. Similarly, the 2 Rupee coin issued in 1991 to commemorate 'Tourism', the 5 Rupee coin issued in 1991 to commemorate 'Commonwealth Parliamentary Conference, and the 5 Rupee coin issued in 1991 to commemorate 'Tourism' can be found only in the UNC sets and the Proof sets.
The rarest coin issued by the Republic of India , as far as I know, is a 2 Rupee coin issued in 1992 by the Calcutta Mint to commemorate 'Land Vital Resource'. The coin is minted in Copper Nickel Alloy. The mintage of this coin is assumed to be less than 500. The Krause does not mention this coin. However, one can find this coin listed in the commemoratives issued by the Calcutta Mint in its official website. It was issued as part of awareness campaign for conservation and promotion of scientific management of land resources. The coin was released by the then Honourable Minister for Agriculture, Mr.Sharad Pawar on 18-11-1993 during the National Resources Conservation Week which falls from 15th November to 21st of November.
There is another interesting coin. Its a 5 Rupee coin issued in 1996 to commemorate '2nd Crop Science Conference'. The conference was postponed all of a sudden and hence a very limited mintage of 11,000 were issued.
In 1968, the Government of India introduced the 20 Paise coins made of brass. Some people believed that these coins contain gold and hence it was melted to make ornaments and parts of weapons. These coins were issued until 1971.
From 1988, a smaller 10 Paise made of ferretic stainless steel was introduced. Some of these coins have an error. The word 'Bharat' written in Hindi language is wrongly written as 'Marat'.
The Government of India is planning to issue bi-metal coins upto the denomination of 10 Rupees shortly. It is expected to be released by the end of this year.
If any more interesting facts are known to you about the Republic India coins, please let me know. I'll post it in this page.