Naturally occurring gold nanoparticles and nanoplates
- R.M. Hough1,*,
- R.R.P. Noble1,
- G.J. Hitchen1,
- R. Hart2,
- S.M. Reddy3,
- M. Saunders4,
- P. Clode4,
- D. Vaughan5,
- J. Lowe6,
- D.J. Gray7,
- R.R. Anand7,
- C.R.M. Butt7 and
- M. Verrall7
- 1CSIRO Exploration and Mining, CRCLEME, ARRC, 26 Dick Perry Avenue, Kensington, Perth, Western Australia 6151, Australia
- 2Centre for Materials Research, Curtin University of Technology, P.O. Box U1897, Perth, Western Australia 6845, Australia
- 3Institute for Geoscience Research, Department of Applied Geology, Curtin University of Technology, Perth, Western Australia 6845, Australia
- 4Centre for Microscopy, Characterisation and Analysis, University of Western Australia, Crawley 6009, Western Australia, Australia
- 5P.O. Box 187, Subiaco, Perth, Western Australia 6000, Australia
- 6Nanochemistry Research Institute, Curtin University of Technology, P.O. Box U1897, Perth, Western Australia 6845, Australia
- 7CSIRO Exploration and Mining, CRCLEME, ARRC, 26 Dick Perry Avenue, Kensington, Perth, Western Australia 6151, Australia
- * E-mail: robert.hough{at}csiro.au
Abstract
During the weathering of gold deposits, exceptionally pure, <200 nm diameter, nanoparticulate gold plates (6 nm thick) are formed. The particles display controlled growth of both size and shape and signs of assembly to form belts and sheets. The gold is associated and inter-grown with minerals formed by evaporation and is interpreted to have been deposited rapidly from saline groundwater during a drying event. The size and morphology of the gold nanoparticles and nanoplates are identical to the products of experimentally manufactured gold colloids. This represents the first direct observation of colloidal nanoparticulate gold in nature, confirming this as an active mechanism of gold transport during the weathering of gold deposits.
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- Received 3 January 2008.
- Revision received 12 March 2008.
- Accepted 24 March 2008.
- © 2008 Geological Society of America
