A new book which explores naturally occurring nanomaterials also sheds light on ‘invisible’ gold particles and nanoparticles of iron oxides. Nature’s Nanostructures edited by CSIRO scientists Dr Amanda Barnard and Dr Haibo Guo looks at how nature’s own laboratory has been producing some of the world’s most advanced nanomaterials for millions of years. We are now starting to see where these particles reside in the environment. In fact, research on gold nanoparticles is helping to explain how rich gold deposits could have formed in the first place.
A Chapter in the book titled Noble Metal Nanoparticles in Ore Systems was written by Robert Hough and Ryan Noble from CSIRO’s Minerals Down Under Flagship and Martin Reich from the University of Chile.
They demonstrate that increasing knowledge of gold nanoparticles is supporting an increasing realisation that nanoscale processes play a key role in the formation of ore deposits.
Colloids may be especially relevant to studies of the production of very large gold accumulations. This gold cannot be accounted for by traditional fluid chemistries with a propensity to only transport low concentration (parts per billion) of gold in solution. Once destabilised in both high and low-temperature solutions, the deposition of gold from colloid is rapid.
The chapter covers: Imaging nanoparticles in natural samples; Gold nanoparticles in hydrothermal sulphides; Nanoparticulate gold and copper in supergene deposits; Colloidal transport; and Future research directions.
Another Chapter is titled Nanostructures of Natural Iron Oxide Nanoparticles and is written by Hiromi Konishi and Huifang Xu from the University of Wisconsin-Madison and CSIRO’s Haibo Guo. It gives a detailed account of some of the most ubiquitous nanoparticles on Earth, iron oxides, which can form in a variety of different sizes, shapes, structures and magnetisation states. These tiny, highly reactive and mobile entities are present in many bio and geochemical processes and regulate the transportation of pollutants and nutrients in soils and waters. The Chapter covers the nanostructures of ferrihydrite, goethite, maghemite, hematite, schwertmannite and akaganéite nanocrystals and their occurrences in nature.
Professor Michael Hochella, former President of the Geochemical Society and current President of the Mineralogical Society of America said “Nature’s Nanostructures offers the first comprehensive and easily understandable look at natural and engineered nanomaterials throughout the Earth system and beyond. This long neglected, yet critical field of study is growing exponentially in application and relevance throughout the Earth, planetary and space sciences.”
Nature’s Nanostructures is published by Pan Stanford Publishing (USA).
Barnard is leader of the Virtual Nanoscience Laboratory at CSIRO. Using thermodynamic theory and first principles computer simulations, she is a pioneer in the mapping of nanomorphology and the environmental stability of nanomaterials (thermodynamic cartography).