Gold exports are becoming more important for countries like Ghana

Cafod says most gold mining takes place in developing states, where it pollutes water, displaces poor communities and damages traditional livelihoods.

The warning comes amid rising costs of gold, most of which goes for jewellery.

Cafod wants mining companies and jewellery retailers to sign a set of standards so gold is mined responsibly.

But some aid agencies such as Oxfam support the sale of gold reserves to finance debt relief.

Gold mining is one of the world's dirtiest industries Cafod

A report last year by the World Gold Council found that the industry brought "substantial improvement" in social and financial infrastructure.

Most mining companies tried to take on local workers and source supplies locally, while royalty and tax revenues from the business contributed to government coffers, the WGC said.

'Dirty' industry

Buyers should be made more aware of the impact of a taste for gold, Cafod - a Roman Catholic charity - said in a report published on Wednesday.

"Gold mining is one of the world's dirtiest industries," the report said.

COST OF COLD Three-quarters of gold comes from developing countries For every gold ring made, there are 18 tons of waste Between 1995 and 2015, roughly half the world's gold will have come from indigenous people's lands, much of it without their consent Source: Cafod

"Gold is a symbol of wealth and power," but "for many developing countries, the discovery... has led to little but poverty and hardship," it said.

Mining can generate revenue and create jobs, but it can also "cause lasting damage to communities and to the environment", Cafod argued.

Gold mining has also been closely linked to conflict, the charity noted - "whether as a result of fighting over the control of precious natural resources or divisions within communities affected by mining".

Toxic process

About three-quarters of the world's known gold has already been mined, and Cafod argues there will be costs for those living above the remaining quarter.

After moving the people, open-cast gold mining involves pouring cyanide solutions onto large areas of countryside. It draws gold out of the rocks but also brings out toxic substances including arsenic.

The process uses huge quantities of water and can contaminate the water table for other users.

In poor countries like Honduras and Central America or Congo in Central Africa, Cafod says local people who live on the land have been moved out and poisoned by polluted water from the mines.