[Rockhounds] 'Bonanza' gold veins in rocks finally explained

[Kreigh Tomaszewski]

Why did some *gold*
<https://www.livescience.com/39187-facts-about-gold.html> prospectors
strike it rich with a bonanza gold vein, while others came up empty-handed?
The credit may go to nanoparticles.

New research reveals that high-grade veins of gold contain clusters of gold
nanoparticles, which is important because it explains how these impossibly
rich aggregations of gold can form in fractures below the *earth*
<https://www.livescience.com/earth.html>. Laboratory experiments have long
found that it's impossible to dissolve enough gold in hydrothermal fluids
to ultimately crystallize out to form thick, high-grade veins of the
glittering stuff. Hydrothermal fluids are heated liquids, warmed by magma
in the earth's crust, which carry complex stews of dissolved minerals and
gases.

The new study, which was published May 18 in the journal *Proceedings of
the National Academy of Sciences*
<https://www.pnas.org/content/118/20/e2100689118>, suggests that these
veins don't come from dissolved gold at all. Instead, they may be
accumulations from so-called colloidal fluids, in which the particles of
gold aren't dissolved, but instead suspended.

"We're the first people to get an image to essentially prove that, yes,
these nanoparticles, these colloids, exist," in geothermal systems, said
study lead author Duncan McLeish, a doctoral candidate in Earth sciences at
McGill University in Montreal.

https://www.livescience.com/bonanza-gold-vein-nanoparticles.html