Washington, June 24 : Australian scientists have for the first time unearthed hard evidence of the discovery of natural gold nanoparticles.
Scientists at the Commonwealth Scientific and Industrial Research Organisation (CSIRO) say, while nanoparticles of gold have been created in laboratories, they have never been seen in nature prior to their study.
The researchers say that new findings made in collaboration with scientists from Curtin University and the University of Western Australia may be helpful in gaining a deeper understanding of how gold can be transported and deposited by geological processes, and thereby enable explorers to find new gold deposits.
"The gold nanoparticles have not been identified earlier because they are transparent to electron beams and effectively invisible," said Dr. Rob Hough, lead author of the study.
H has revealed that his team discovered the particles in Western Australia.
"In the southern areas of the State, groundwater is very salty and acidic. This water dissolves primary gold and re-deposits it as pure gold crystals on fracture surfaces and in open pore spaces," he said.
"On investigation of these crystals, there appeared to be a dark band across them. However, high magnification imaging showed the band was in fact, a mass of gold nanoparticles and nanoplates. These are identical to those being manufactured in laboratories around the world for their unique properties," he added.
The researcher said that there was not gold visible when clays from the fracture surface were analysed, but the analysis did show that the clays contained up to 59 parts-per-million of gold.
The research team concluded that the nanoparticles of gold they had imaged represented the 'invisible' gold in the clay, and that the nanosized gold was common in similar environments.
"The gold nanoparticles have not been identified earlier because they are transparent to electron beams and effectively invisible. However, they are probably a common form of gold in this type of natural environment worldwide, where saline water interacts with gold deposits. They also provide the first direct observation of the nanoscale mobility of gold during weathering," Dr. Hough says.
A research article describing the study has been published in the journal Geology.