A small-scale miner in Tanzania, who became an instant millionaire after selling three rough Tanzanite stones for $5.4m (£4.1m), has told the BBC he is optimistic that he will make other big finds of the rare gems in the near future.

Saniniu Laizer - who has been in the mining business in northern Tanzania for more than 15 years - said this was the first time he had struck such luck.

He sold two stones to the government in June for $3.4m, and a third on Monday for $2m.

Mr Laizer said he was confident of discovering more of the precious stones - found only in northern Tanzania - because of analysis conducted by his geologist.

Some have envied Mr Laizer, while others have been inspired by him.

He warned that the business was not as easy as people think.

"It is very expensive to operate the mines. Most of the times we get loans, while at other times we are forced to contribute money among ourselves as small-scale miners," he told the BBC.

Mr Laizer has diversified his business interests and has ventured into other areas, including the construction of shopping malls.

He has also used part of his fortune to build a school and a church in his community.

"Farmers’ and pastoralists’ kids are often not attending school because schools sometimes are very far and children spend most of the time looking after animals," he said.