A miner on Tanzania became a millionaire overnight after selling two rough Tanzanite stones - considered as the country's biggest find ever.

The miner- Saniniu Laizer- earned a whopping £2.4m ($3.4m) from the Tanzanian Ministry of mining for the gemstones.

The two Tanzanites had a combined weight of 15 kilograms, the media reported.

It may be mentioned here that Tanzanite is only found in northern Tanzania and is famous for its extensive use in ornaments.

Tanzanite is one of the rarest gemstones on Earth and geologists in Tanzania have estimated that the gemstone would be entirely depleted within the next 20 years.

Tanzanite's appeal lies in its variety of hues, including green, red, purple and blue and its value is determined by rarity.

A finer colour of the stone means a higher price for it.

The two stones were mined by the miner last week it respectively weights 9.2 kilogram and 5.8 kilograms.

The two stones were sold on Wednesday (June 24) during a trading event in the northern region of Manyara.

Before this discovery, the largest Tanzanite rock to be mined weighed 3.3 kilograms.

Speaking about his plans after the sell, the 52-year-old miner said that he would feast on meat and party to celebrate the find and the deal.

Moreover, he also plans to invest in his community in Simanjiro district in Manyara.

He also plans to construct a shopping mall and a school near his home for the welfare and benefit of several poor people.

He said the school would be of great help to hundreds of poor children whose parents can't afford to send them to school.

Speaking to BBC Laizer said, "I am not educated but I like things running professionally. So I would like my children to run the business professionally."

Tanzania is a country in East Africa within the African Great Lakes region and it borders Uganda to the north, Kenya to the northeast, Comoro Islands and the Indian Ocean to the east, Mozambique and Malawi to the south, Zambia to the southwest, and Rwanda, Burundi, and Congo to the west.

Mount Kilimanjaro, Africa's highest mountain, is in north-eastern Tanzania.