Gold down under
Sample: High grade gold ore
Mine: Kundana Mine, Australia Primary Commodity: Gold (Au) Deposit Type: Lode / orogenic Take a look at the rather dull ore in photograph A. It may surprise you, but this sample contains approximately 15-20 grammes of gold per tonne. When you think that the average gold wedding ring contains around two to three grammes of gold, that’s a lot of wedding rings in one tonne of rock!
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Fool’s association
Despite its high gold content, it is not possible to see the gold in this sample with the naked eye. However, photograph B, taken through a microscope, shows you a single Kundana gold grain perched on the side of the mineral pyrite (FeS2) – a mineral more commonly known as fool’s gold. Note the horizontal scale of photograph B – one fifth of a millimetre! Knowing this, you can begin to understand just how small gold at Kundana can be. |
Photograph A: a single Kundana gold grain perched on the side of the mineral pyrite
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Why is this sample in the ore collection?
Museum scientist Dr Chris Stanley collected the Kundana ore suite in July 1989. Around this time, geologists were interested in all things gold related and they wanted to know where, when, why and how gold came to be present in different geological environments. This led to Dr Stanley co-authoring an award-winning scientific paper (Knipe et. al., 1992) that looked into the role that sulphide minerals – such as the pyrite grain in image B – play in the formation of gold deposits.
Visit window four and window twenty one to read about more gold in the Museum’s ore collection.
References
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Museum scientist Dr Chris Stanley collected the Kundana ore suite in July 1989. Around this time, geologists were interested in all things gold related and they wanted to know where, when, why and how gold came to be present in different geological environments. This led to Dr Stanley co-authoring an award-winning scientific paper (Knipe et. al., 1992) that looked into the role that sulphide minerals – such as the pyrite grain in image B – play in the formation of gold deposits.
Visit window four and window twenty one to read about more gold in the Museum’s ore collection.
References
- Knipe, S.W., Foster, R.P., and Stanley, C.J. 1992. Role
of sulphide surfaces in sorption of precious metals from hydrothermal fluids.
Transactions of the Institution of Mining and Metallurgy, Section B, May-August.
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