Mercury will dissolve gold, silver and lead very readily. Dental
amalgam is made of silver and tin with mercury added to make a paste
what is workable. Mercury is still used in south America to recover
gold, most miners die by the time they are 30 so it is not
recommended. In chemistry labs they use sulfur to clean up mercury
spillages, this reacts and forms cinnabar, mercury sulfide. When you
could take mercury to a scrap metal dealer we used to dissolve lead
in it to increase the weight but now only specialist refiners are
allowed to handle it [in the UK] and we basically get our metal back
and pay a distillation fee so it doesnt happen any more. We also
used to have mercury vapour vacuum pumps on one of our electron
microscopes that was built in the 1960’s, decommissioning that was a
nightmare as that wasnt the only hazard. I know of no examples where
mercury has been used to store gold as a matter of choice, I suspect
it is as likely as a mercury tipped bullet much loved by thriller
writers [see metals dissolving in mercury]
As an aside when I was a kid I saw a televisions show about
mercury, and they were floating solid steel objects, like a 12"
adjustable wrench, on a large pool of mercury just like they were
toy boats. An octogenarian coworker of mine says that when he was a
kid they would play with mercury. You could rub it on a penny, and
it would "silver" the penny. Sometimes I'm stunned that he's lasted
so long.
Not only bits of metal float on mercury but, to this day, many
lighthouses still have the entire lamp/lens housing floating on a
ring-shaped pool of mercury. It is the most friction-free bearing
available and you can easily push the whole lens assembly round with
just one hand even though it weighs several tons.
As to coating coins - when I was just a lad at grammar school in the
early 60’s, we would often have a chemistry lesson for the last
period in the afternoon. One of our tricks, though I’m now ashamed
to admit it, was to mercury plate a penny ( we still used the large
old British pennies then) and offer it to the bus conductor on the
way home. More often than not, especially if their attention was
diverted by other rowdy kids, they would give you the change for
half-a-crown, a coin of similar size and silver in colour but worth
30 pennies…
They would cut a core out of a potato, pour in the mercury
containing the gold and seal it back up with the remainder of the
plug. They then would place the potato in the camp fire and allow
the mercury to boil off leaving the gold behind.
Usually, when I regale my husband with jewelry tales, he listens
about as well as I listen when he talks about sports. Imagine my
surprise from his dry response to this story, "So that’s where they
got the name of ‘Yukon Gold Potatoes,’