July 17, 2008 -- Miniscule triangular and hexagonal plates of gold less than 20 nanometers thin and identical to those manufactured by humans have been found occurring naturally in salty groundwaters of Western Australia.
The Aussie nano gold in the water gets as thin as six nanometers and previously escaped detection by electron microscopes, say Australian researchers. Nano gold is being developed for use in for drug delivery, optics, superconductors and catalysts, but until now, it was thought to be entirely manmade.
"It's very, very similar to the colloidal gold people have been growing in laboratories," said Robert Hough of the Mining and Exploration branch of Australian government's research agency, CSIRO. He is the lead author of a paper describing the nano gold in the July issue of Geology.
The gold nano particles had appeared as ghostly grey shapes in scanning electron microscope (SEM) images. By applying what's called "high-resolution secondary electron imaging in a field emission SEM," Hough and his team were able to look directly at the ultra thin gold particles.
"I am surprised," said Pablo Jadzinsky who uses nanogold in organic chemistry research at Stanford University.
Nano gold is currently a hot topic for research and development, Jadzinsky said, and getting hotter.
At the moment, labs make their own nano gold by dissolving larger pieces of gold and growing the nano crystals. But they have suffered from some of the same difficulties as the geologists looking for natural nano gold: being sure they know just what sort of nano gold particle they are dealing with.
Whether natural nano gold will be of any use to labs is unclear, said Jadzinsky, because it depends on how hard it would be to purify the salty ground waters and isolate just the sort of nano gold that is desired.
Geologists aren't worried about laboratory applications, however. Instead they are looking at how the nano gold could lead to large, extractable deposits of the precious metal.
"It has big implications for exploration," said Hough. "It's really a fundamental of how gold moves around."
And now that they know how to look for the nano gold, there is a way to look for signs of gold deposits anywhere there is salty groundwater, said Hough.
"Previously we didn't have the tools to look at (nano) gold directly," said Hough.
Now they know: Thars gold in them thar ground waters.
Related Links:
Larry O'Hanlon's blog: Earth Impacts
How Stuff Works: How Could Gold Save My Life?
Commonwealth Scientific and Industrial Research Organization (CSIRO)
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