Pink diamonds cost at least 20 times more than processed white diamonds and only 40 to 60 pieces are available worldwide, with each stone weighing 40 to 60 carat.
They are mined at Rio Tinto's Argyle mine in Africa and processed at its cutting and polishing facility in Perth.
The Perth-based facility of the global mining major processes only around 50 such diamonds every year, making them the world's rarest gems, Bruce Cox, managing director of Rio Tinto Diamonds, said in Mumbai.
According to Jean-Marc Lieberherr, general manager (diamond sales and marketing), Rio Tinto, 30 to 40 companies have participated in the tender but they may not get to lay their hands on the pink diamonds because of stiff competition from buyers from other countries such as China and Hong Kong.
"Indians lack understanding about pink diamonds and we are here to educate them, highlight the distinctions with other available diamonds in the world," Lieberherr said.
Rio Tinto is betting big on the Indian market, which it sees growing at 15 per cent annually till 2020 because of favourable economic prospects amid rising disposable income of the average middle class.
Participating in the current tender would open a window for Indian customers to get this diamond in the future, Lieberherr said. Rio Tinto mines colour gemstones in its Argyle mine, while the Diavic mine in Canada yields white diamond, which is about 70 per cent of what India processes.
Speaking on the occasion of Rio Tinto completing 20 years of operations in India, Bruce said that India contributed about 73 per cent to the company's sales and 70 per cent of diamonds it produced were cut and polished here.
About 10 per cent of diamonds produced by the company are retailed in India through 10 dedicated direct outlets.