Finding gold in fool’s gold

Shiny yellow crystals — Fool’s gold is yellow and shiny – much like real gold!
*Image: Wikimedia commons/Uoaei1 CC-BY-SA 4.0*

Back in the California gold rush, many people were tricked by a shiny yellow crystal known as fool’s gold. Now, more than 100 years later, scientists are flipping the script. Australian and Chinese researchers have found where real gold hides inside fool’s gold!

To start with, the scientists looked at fool’s gold with a powerful scanning electron microscope. They spotted many dislocations, imperfections in the crystal where the atoms weren’t lined up quite right.

Digging deeper, they used an atom probe to peer into a dislocation. This cutting-edge technique makes 3D maps of the chemicals in a tiny sample. The researchers found that dislocations are ‘decorated’ with gold!

This isn’t the first time gold has been found in fool’s gold. In fact, there are already several mines around the world that dig up fool’s gold, but it takes a huge amount of energy to get the gold out. One common technique involves roasting the crystals until they turn into rust. In some cases, just 6 grams of gold are found in a tonne of roasted fool’s gold.

As more gold is hiding in dislocations, there might be easier ways to get at it. For example, the researchers think that the right type of bacteria could attack dislocations and release gold. That sounds like a smarter way to get the gold out of fool’s gold!

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