Everyday rickety homes in a remote Myanmar village inch closer to a cliff edge as bulldozers owned by the nation's elite claw the earth beneath them, ravenously hunting jade to feed China's multi-billion dollar demand.

"That's our space. Now they're entering through the places where we live," said Daw Kareen, pointing at a water-filled ravine in the jade mining area of Hpakant in northern Kachin state.

The houses precariously perched alongside sometimes collapse, added the 44-year-old, in an area where local protests have long gone unheard by authorities in the "grip" of mining firms.

Secluded Hpakant, encircled by raging ethnic war, is a treasure trove for Myanmar's wealthiest, who monopolise the world's primary supply of a stone that has almost mystical reverence in China.

Jade was the preserve of the military under junta rule and despite a fanfare of reforms, a new government dominated by former generals has maintained secrecy around the industry since coming to power in 2011.

In the months ahead of key November elections, likely to be swept by Aung San Suu Kyi's opposition party, locals report an accelerating frenzy of environmental destruction as firms dynamite hills and gouge deeper into the earth.

Fears of vast corruption centre on the discrepancy between official Myanmar jade sales and recorded Chinese precious stone imports from the country, which last year amounted to $3.4 billion and $12 billion respectively.

But in a new report published Friday advocacy group Global Witness estimates the value of jade produced in 2014 was actually far greater at $31 billion -- nearly half of impoverished Myanmar's GDP.

It says most of the profits are going to powerful military and ex-junta figures as the best jade is smuggled directly into China across the border near Hpakant.

- 'Hell on earth' -

Once cloaked by dense jungle, the area is now ringed by naked hills, exposing it to frequent monsoon landslides and a ferocious tropical sun.

Local activists say dozens of miners have died in recent months on unsteady mounds of rubble left by mechanised diggers, or falling to their deaths on illicit nighttime jade hunts on the sheer cliffs.

"It is hell on earth -- have no illusions," said an aid worker with knowledge of the region who asked not to be named.

Abundant heroin is commonly used to dull pain and hunger during long day shifts.

But Hpakant is also a place of legendary promise, where everyone knows someone who made their fortune.

Any seemingly-nondescript boulder might harbour a vivid green heart and miners become expert at tapping through masses of grey stones, listening for the distinct tone that signals jade.

Thein Zaw Win was driven to the wild northern frontier by money problems at his family farm in central Monywa three years ago.

But the 20-year-old has sent $4,000 a year home from scouring the waste rubble.

"If I dig everyday in this hole I hope someday I'll get rich," he said, carrying a chunk of jade he had just found.

- 'Stone of heaven' -

Praised by Confucius as a symbol of virtue and known as the "stone of heaven", jade has been prized in China for centuries.

Nephrite, often a milky peppermint, has long been mined in China, but it is the translucent green jadeite, or "imperial jade", that is most sought after -- and almost all the world's supply comes from Hpakant.

While evaluating a chunk of gold is a simple matter of carats and ounces, jade prices are judged on a multitude of subtle variations of shade, lustre and the craftsmanship with which it has been carved.

"A bracelet can be $5 or $5 million," said a Myitkyina businessman, asking not to be named.

In glitzy shops in Hong Kong and China, monied consumers can select from an array of jade jewellery and ornaments -- ranging from the colour of kingfisher wings to "mutton fat" cream.

"The younger generation want to have a pair of jadeite earrings or a necklace," said Vickie Sek, Asia head of jewellery for Christie's in Hong Kong.

But she added the highest quality Myanmar jadeite is becoming rarer.

In Kachin locals fear they are losing a crucial natural resource.

The Myitkyina businessman said bigger machines were now being used to remove the jade as quickly as possible, estimating at least 70 percent of the best quality stones are smuggled over the border.

"In 50 years we'll be visiting our jade in China," he said.

Global Witness has linked the trade to Myanmar's military, cronies and drug barons, and says it fuels Kachin's bloody conflict.

It wants jade to undergo the same transparency reforms that swept the oil and gas industry as part of a bid to join the Extractive Industries Transparency Initiative, an international scheme ensuring ordinary people share the rewards of a country's natural bounty.

"You have to question a reform process that misses the most valuable industry in the country," said Juman Kubba of Global Witness.

In her recent Kachin election tour, Suu Kyi did not visit Hpakant or refer directly to jade, but her promise of clean government drew cheers in the state.

"I really want a government that cares about us," said Daw Kareen, a widow who supports two children.

But she fears "if the same people (rule) as in the old times, there won't be any changes".