Stunned miners have unearthed the world's most valuable piece of jade - an 18ft monster worth £140million.

 

Workers were excavating rare gems at a remote mine in Kachin State, Burma, when they stumbled across the huge jadeite rock.

 

The remarkable stone weighs a staggering 175 tonnes, measures 9ft high, 18ft long and 18ft wide.

 

Pictures from the scene of the recovery show local politician U Tint Soe standing next to the giant gem as it towers above him.

 

The rock - which will appear its distinctive green once cleaned - is second only in size to the a carved statue at the Jade Buddha Palace in China which weighs 260 tonnes.

 

Miner Sao Min, 44, said: 'We thought we had won the lottery. But this belongs to the country. It is in honour of our leaders.'

 

U Tint Soe said: 'The jade is as big as two small houses that are 9ft square.

 

'I assume that it is a present for the fate for our citizens, the government and our party as it was discovered in the time of our government. It's a very good sign for us.'

 

Burma - or Myanmar - is the world's largest producer of jadeite - and the 50 billion dollar a year industry represents half of the country's GDP.

 

The wholesale price of Jadite - most valuable form of the gem - from mines is around £820 per kg - but prices can reach is much as £1,150.

 

It gives the rock found on Thursday an estimated value of $174.6m - the highest for any single piece of raw Jade.

 

And the price per kg could be up to twenty times higher once it has been polished and shaped - giving it an astronomical potential price tag in the billions.

 

The boulder will be sent to China where it will be carved up into expensive jewellery and sculptures.

 

Chinese jade expert Frank Xiao, a dealer in Shenzhen, southern China on the border with Hong Kong, said: 'This is a beautiful find. There are many negotiations but it's likely to be coming to China.

 

'It will make many beautiful necklaces and bracelets in the future. And plenty of statues for homes in China.'

 

An 18 tonne nephrite jade boulder was found in Canada in 2013 with a value of around £1.6million.

 

The price of jade has rocketed since then and Jadeite - the form most common in Burma - is worth significantly more.