GOLD nuggets might grow underground like potatoes, scientists have discovered.

Nuggets: grow them yourself

The highly prized chunks of gold may be the product of generations of soil microbes at work.

Researchers from the Cooperative Research Centre for Landscape Environments and Mineral Exploration grew gold nuggets in the lab.

Frank Reith studied microscopic formations on the surface of alluvial gold and discovered bacterial remnants on the gold flakes.

"I found some areas on gold flakes that were covered with apparent . . . traces of bacterial action," he said.

A stain for DNA returned a positive result.

When he tested his findings in the lab, tiny fungi and bacteria in the soil deposited atoms of gold within days.

It is believed nuggets form metres below the surface as a result of microbial action and are gradually exposed by wind erosion and shrinking of the surface soils.

"Possibly these secondary nuggets grew like potatoes in the soil, although it may take millions of years to form a really large one," said CRCLEME chief executive Dr Dennis Gee.

The discovery could help in exploration for new fields of the precious metal.

Herald Sun (Australia)

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