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Dissolved gold in mercury to deter thieves?


#1

I was reading an “instructable” recently on instructables.com about
how to mold concrete inside an empty glass light bulb. In the
comments following the instructions, someone suggested trying it
with a compact fluorescent “spring” bulb. The topic of the comments
quickly turned to mercury and the dangers therewith.

Someone commented that (quote) “Jewellers keep their gold and other
such expensive metals dissolved in mercury because most of the times
the thief either doesn’t know what it is or how to use it. So he gets
caught.”

I replied “no we don’t”, and received comments that it was done with
a Nobel prize during WWII to protect it from the Nazis, and that
someone else had read about it in a TechRepublic Geek Trivia
article.

This is probably the weirdest thing I’ve ever heard about the
jewelery trade. I’m sure nobody does this now, but is there any truth
to this ever having been done in the past? I can’t even fathom how
one could dissolve gold in mercury to begin with, let alone how you
could get it back out again to use it…

Curious but certainly not intending to try it,

Kathy Johnson
Feathered Gems Jewelry
http://www.featheredgems.com
http://www.fgemz.com


#2

Hi Kathy:

The dissolved nobel medal was true, but it was done with Aqua Regia.
It was two of them, actually. James Franck’s and Max von Laue’s,
both for physics. (not Neils Bohr’s as is usually noted.) Each of the
early nobel medals consisted of 200g of 23K gold. Franck and von
Laue were both jewish physicists who came through Neils Bohr’s
institute for theoretical physics in Copenhagen in the early days of
the war, on their way to escape. They left their medals with Bohr for
safekeeping, It being a crime to export gold from Hitler’s Germany.
When the Nazis occupied Denmark, Bohr was left with the problem of
how to hide the medals. Burying was discussed, but eventually the
chemist George de Hevesy dissolved them in aqua regia, and they spent
the war peacefully in a nondescript bottle on the back shelf of the
lab, waiting to be reclaimed and recoined after the war, which they
were. Professor Franck received his recoined medal at a ceremony at
the University of Chicago in 1952.

(source: http://nobelprize.org/nobel_prizes/medals/)

As far as dissolving gold in mercury for ‘hiding’…errr…yeah,
it’d dissolve it, but at those sorts of quantities, it’d turn into a
yellowish paste looking stuff, and the amount of mercury you’d need
would be insane. Nevemind the intense joy of trying to get the gold
out of the mercury later. That may have been a trick that was used
once upon a time, in a galaxy far, far from safety regulations, but
nobody who knows any better is doing it now. (Yeah, I know, they’re
still doing mercury extraction in South America and Africa. And look
at what they’re doing to themselves and the landscape around them
while they do it.)

Shudder.
Brian.


#3

Well, if anyone has some ideas about how to get mercury and gold
separated without getting into to much danger, I would like to hear
about it. I have a customer who must have been tuned into the same
alternative reality who gave me a little vial that contains gold,
mercury and water. I am not sure why. This gold was panned by
himself and his late girlfriend, so he wants me to cast a memorial
piece for her using it. It means a lot to him, but sort of scares me.
We are only talking about a very few grams of material.

Maybe 5 grams.
Stephen Walker


#4

Yes, gold will dissolve in mercury. This has been a method of
extraction for years. Mercury ore deposits were one thing that the
Spanish looked for when they came to California. The Spanish Almaden
mines were mined at the time of the Romans. The New Almadan (I think
that’s the name) park west of San Jose is a good example of early
mercury mining and refining. You will see a display about it in the
hotel replica at the Frontier Villiage on Coyote Creek south of San
Jose. Funny thing, when the records are checked, there were plenty
of deaths in the early mercury town, but no live births. I have
talked to one man who remembers the fellows who panned the black
sands at Ocean Beach in San Francisco during the depression. The
fellows would take their black sand and pour it into a hole in a raw
potato…put the stopper back in and then roast the potato over a
campfire. The gold would form a little bead as the mercury fumes were
driven off. Of course they didn’t eat the potato.

If you made a campfire ring out of mercury ore the fumes might kill
you during the night…like they did one hunting party.

When I was in the California Bureau of Mines display when it was in
the ferry building in San Francisco during the eighties, I saw a
glass display case broken on the top. Inside was gold ore and mercury
droplets. Someone figured they would harvest a little. But I doubt if
it would have worked. The ore was a gold terreluride.

Here in Idaho one fellow has told me he knows of one mountain stream
with pools of mercury in the bottom from an early gold rush.
However, how much gold could you get in a flask of heavy mercury??
How much surface area is required for adsorption? If a nobel prize
were put in there, it would not come back out in the form it
originally was in if it was possible to absorb it.

Rose Alene


#5

Kathy,

Gold does dissolve in mercury. It also looses all structure. Lots of
mercury and you end up with a mix which sort of feels like mercury
with sand in it. A drop of mercury on a ring and you need a new ring.
I have seen a few distraught repair customers wondering why their
yellow wedding ring suddenly turned white. You get recognised as a
jewellery wizard when asking about the broken thermometer, despite
the bad news

It is possible to separate the two metals by boiling off the mercury
(google Fire Guilding) but the process is VERY hazardous and illegal
these days without a lot of fancy equipment to recover all of the
mercury. Experience from decades ago when death was a distant
problem, and I still have a few grams of gold in an amalgam.

Jeff
Demand Designs
Analog/Digital Modelling & Goldsmithing
http://www.gmavt.net/~jdemand


#6
This is probably the weirdest thing I've ever heard about the
jewelery trade. I'm sure nobody does this now, but is there any
truth to this ever having been done in the past? I can't even
fathom how one could dissolve gold in mercury to begin with, let
alone how you could get it back out again to use it... 

I’d agree that jewelers don’t store their gold dissolved in mercury,
simply because a good safe is so much easier and safer. But gold does
indeed dissolve in mercury. That behavior is the basis of the old
style method of gilding silver with gold, as well as ancient methods
of refining gold, still tragically used today in many primative gold
mining operations, especially in latin america, where it’s use not
only poisons the people doing it, but terribly pollutes the rivers
and waterways downstream. All you do to dissolve gold in mercury is
simply put it in. Like solid silver added to molten gold, the gold
dissolves in the molten mercury (liquid at room temperature, but
still a molten metal, after all). In primative refining, the ore is
mixed with mercury, where gold in the ore dissolves in the liquid.
That’s then seperated from the remaining solid ore (sands, etc) and
the mercury is heated to vaporize it, leaving the gold. At best, this
is done in some version of a primative still so as to recondense and
recover the mercury, but usually that’s only partially efficient,
resulting in mercury contamination of the area, and slow poisoning of
the people doing it. In fire gilding, the same method is used. An
amalgam (liquid to pasty mix of mercury and gold) is spread out on
the silver item to be gilded, and it’s then heated to drive off the
mercury, leaving the gold as a layer on the surface. Similar
unfortunate consequences (short lifespans, early death, neurological
damage, etc) as with the refining operations doing this, are why
fire gilding is not generally done much today…

As to hiding or disguising gold items with mercury, though I’ve not
heard of it being specifically done, it might have been. Coating a
gold item with mercury causes the mercury to diffuse into the gold
surface. If there’s enough, this results in a fairly white metal
color, rather than a gold color, with some surface degredation, such
as to the polish, but not necessarily all that much (a good polishing
would be required later. Again, heating to a low red heat would
vaporize the mercury again at a later date. I can see how such a
plan might have been used in some desperate wartime situations, but
certainly not as any sort of routine practice. Probably, I’d guess
painting the object would have been easier… In both cases, the
obvious density / weight of the object might still easily give away
the deception. Imbedding the object in a ceramic covering (the gold
could withstand low temp firing of the clay) might work better, since
then the larger ceramic might not be quite so obviously too heavy…

Peter Rowe


#7

Well, I certainly didn’t dissolve gold in mercury, but back in the
1980’s, I certainly left my gold mixed in copper, as I showed in my
refining post on the orchid blogs. This was done to fool the gold
cops in South Africa when they sprung a surprise visit on you to
check you gold register, gold weights and gold working licence.
South Africa has draconian gold laws and failure to comply could, and
still does, land you in jail quite quickly.

They never did figure it out, though.
Cheers Hans


#8

Hi Kathy,

It’s funny that you should hear that, I just recently watched a
documentary on gold miners in South America. To get the small
amounts of gold in the river banks, the miners take a large bottle
of mercury, about 4 oz and dump it in a 50 gallon drum and add mud
and water from the water. Then the miners stand in the drum and stomp
in the mud and mercury and I guess the mercury bonds to the gold in
the mud. When they have stomped for a while, they then collect the
mercury and put it in a bowl and burn the mercury off with a torch
and then the miners are left with just gold. I’m sorry to let you
know this is where some gold comes from and it is not traceable…
They interviewed the miners and they said they know that it is
hazardous to their health, but it makes money and right now he felt
ok, so he was going to keep doing it until he got sick. I think I
watched the show on the Discovery Channel. When they were
interviewing the miners they said that the gold has been collected
this way for many generations.

All I can say is WOW,
Lauren Stineman


#9

Hey Kathy, I don’t have any history but I can tell you a bit about
gold and mercury. Gold doesn’t dissolve in mercury but one has a
great affinity for the other. I suspect the mercury was used to coat
the gold to hide its appearance. A retort is used to vaporize and
recover the mercury. Mercury, if vaporized using a torch without a
retort will make a poisonous cloud and contaminate the surrounding
area. Don’t do this! Old time miners used to use mercury on slick
plates to pick up any fine gold flowing through the sluice. Their
poor recovery methods resulted in a lot of mercury being spilled into
the rivers they worked. Modern day dredgers have extremely effecient
recovery from their gold dredges and will also catch mercury that has
been in the rivers for 100+ years as well as lead from fishing
weights and shotgun shot, disposing of it in a safe manner.

Be safe, Jim Doherty


#10
I'm sure nobody does this now, but is there any truth to this ever
having been done in the past? I can't even fathom how one could
dissolve gold in mercury to begin with, let alone how you could get
it back out again to use it 

A couple of comments on the foregoing statement: Mercury was commonly
used in placer mining as a way to capture fine gold that would
otherwise be lost. Gold, silver, and copper all readily alloy with
mercury to form an amalgam. In the case of gold, the mercury in the
amalgam was driven off by heating in a retort and the mercury
condensed back into liquid mercury for re-use. This is a hazardous
operation cosidering the toxicity of mercury vapor, so it is not to
be recommended.

To this day, much of the gold one can recover by panning the gravels
in California’s Gold Rush country is so contaminated with mercury
that it is gray rather than yellow, but it does recover its natural
color by heating and driving off the mercury, something I discovered
by personal experience after I had panned a spot along the Yuba
River.

Richard Davies


#11

Stephen,

I have never performed this act, but I had an uncle that was a
geologist and rocky hound. He told me about how miners use to use
mercury to pick up the very fine almost invisible pieces of gold
while panning. 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. I can’t say if
it truly did work or not. That was the story I was told. If you try
this make sure you avoid the fire until it is out. Lord only knows
what the vapor will do. This is definitely a hazard to perform.

Usual disclaimers of course.

Ken Moore
www.kenworx.com


#12

I have never heard of gold being disguised my making it into an
amalgam, it would sure work but there are much better ways of hiding
or securing gold. I remember a book titled “The Golden Keel” long ago
where the ballast of a yacht which is traditionally tons of lead, was
made of gold for some sort of smuggling operation.

Because mercury is already molten at room temperature it will
readily dissolve gold until the melting point of the gold/mercury
alloy exceeds the room temperature. The amalgam will then be a stiff
paste which will solidify in time as the mercury evaporates.

To free the gold from the mercury simply heat the amalgam and boil
off the mercury (the mercury can be condensed and recycled). Needless
to say ingesting mercury vapors in any way is the ticket to agonizing
debilities and slow but certain death.

It was mentioned just recently in the topic of buying customers’ gold
that some unscruplious individuals will put a 3mm skin of gold over a
brick of lead. Why not reverse the process and stamp the brick “pure
lead”…maybe not a good idea considering the price of lead these
days!


#13

First I have to say you can’t even start to believe what you read or
see on the internet!!! As been proven by the faked and doctored
U-tube vid’s and the other sites even when they say it’s not. Wiki
has been wrong and it takes a while to correct it. Boric acid is
poisonous and can kill when ingested. As it is mixed up for eye wash,
and placed in the fridge. As it is tasteless, colorless, orderless.
It is mistaken for ice water in the hotter months and people drink
it. At one time it was the most common type of home accidental
poisoning, during certain months.

To find out you have to go to the MSDS for chemical companies, and
not rely say on google. or other search engines or sites. After all
anybody can and do put anything on the net and call it gospel.

Instructables.com and the like have more ways of committing suicide
by stupidity than any book on the subject. Just because some nut
does something doesn’t mean the next party will be as lucky. Like
all these kids getting hurt copying the stupid people tricks on TV
and the u tubes. Is now the number one reason for emergency room
visits.

Mercury and gold, having spent 34 years in the educational system of
a large city. and being called to a room were a science teacher or a
teacher doing science in the lower grades. Crying because they were
showing the kids Mercury in their hand with their rings still on the
fingers. And bam there goes the ring or band, if there was stones
they are what is left plus some of the alloy material or some kind
of spongey gung. The last time was less than 5 years ago, I guess
some people really do live under rocks and don’t pay attention to
the world around them.

Wife did it in the kitchen 30 years ago after I just told here to
take her rings of when she was going to show the kids coating a dime
with Mercury. As she was smarter than me, why would she listen.
Wedding band went the way of a dissovlved solid in an eyeblink. (of
course this was before the danger about playing with it was know)
The look on her face told me that silence was the better part of
valor at the time!

It will only lighten your bank account, as they don’t pay more for
Mercury with gold dissolved in it. If you can find somebody to buy
it.

I vote also for a good floor safe or one bolted to the floor!


#14

As an aside to this thread… There is this neat little tool
formally made here in our neighborhood. It is a mercury detector
originally invented to help prospect for gold. It has a kapton film
inside that is coated with gold (vapor deposition). To test for
mercury in the air the electrical resistance of the film is
recorded. A small quantity of atmosphere is drawn into the unit. The
film is heated and it absorbs any mercury. The resistance is read and
the difference from the first reading is used to generate the parts
per million at that location. Gold and mercury are indeed often found
together. By working around an area and testing in different
locations a map can be developed that would point to the area most
likely to have a gold deposit. You can see the shoe box size devise
here…

http://www.trs-environmental.com/model/AZI_J405_HG_ANALYZER.aspx

Ok, back to work!
Bill


#15
Well, if anyone has some ideas about how to get mercury and gold
separated without getting into to much danger, 

Stephen, it’s really very simple - you distill it. The difficulty is
in the need for a completely sealed system. But in essence you just
heat the amalgam, mercury vapors come off of it, and then you cool
them and they condense back into liquid mercury. Gold on one side,
mercury on the other. For five grams I might use the
potato-in-the-campfire method, which I’ve also heard.

http://www.donivanandmaggiora.com


#16

Hi Kathy,

Gilding (gold plating) of metals used to be done by the ‘Mercuric
Gilding’ method up to the early years of the 20th century. In this
method, pure gold was dissolved in mercury to form an amalgam. The
pure gold - usually in the form of a powder precipitated from a gold
bearing chemical solution - was simply put into mercury and left
until the gold ‘dissolved’ - it didn’t really dissolve but
amalgamated with the mercury to form a composite metal. When all the
gold was combined with the mercury, the liquid was squeezed in a
twist of chammy leather and the excess mercury passed through the
pores of the leather leaving the amalgam as a mass with the
consistency of butter. This was cleaned using Nitric acid and it was
rubbed onto the part to be gilded - silver, brass or whatever. The
slight excess of mercury left in the mixture amagamated with the
surface of the metal and bound the gold amalgam to it. Then the whole
piece was heated, usually over a charcoal fire, which drove off the
mercury and left the gold clinging to the metal. It was these mercury
fumes as they were driven off by the heat that were the dangerous
part as, when breathed in, they would condense in the lungs back to
metallic mercury and this would make its way into the bloodstream
and, from there, into the brain and liver particularly. A long term
build-up could be deadly as the mercury corroded away the tissue it
sat in. One of the biggest users of mercury in the 18th and 19th
centuries, was the hat trade where it was used in making felt hats
and was evaporated into the air. Because of its effects, we get the
term ‘Mad as a Hatter’. When the mercury had been driven off the
gilding, this looked a dull yellowish grey colour and was vigorously
brushed with a stiff bristle brush and ‘Cream of Tartar’ (Potassium
Aluminium Tartrate I think) to polish it and restore the brilliant
colour of the gold. As to storing gold in mercury, I think that this
is likely to be an ‘urban myth’ although it would be perfectly
possible provided you could store the mercury safely and securely.
The gold could be recovered as pure gold simply by heating the
mercury.

Best wishes,
Ian
Ian W. Wright
Sheffield UK


#17

Mercury dissolves a number of metals to make soft metal alloys called
amalgams http://www.etymonline.com/index.php?term=amalgam which is
where silver amalgam fillings get their name, easy working
properties, and controversy. In addition to sluice boxes, miners
that were panning for gold would add mercury to the bottom of their
pans to catch gold dust. The very dense mercury and mercury/gold
amalgam would stay in the pan (mostly) and the sand and gravel would
float on the surface where it was more easily washed away. In
particularly badly polluted rivers people have overturned rocks in
the riverbed and exposed droplets of mercury that settled and
remained presumably from many decades ago.

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.

Jason


#18

The Arizona Mining and Mineral Museum in Phoenix has a 19th century
stamp mill set up on its grounds. That thing is two stories high and
processed tons of ore a day and the concentrate was treated with
mercury to recover the gold. They used to run banks of them.

It’s astonishing more miners didn’t die.

RC


#19
<snip> and received comments that it was done with a Nobel prize
during WWII to protect it from the Nazis

According to the Nobel Prize website, it is rumored that the medals
of Max von Laue and James Franck were dissolved in aqua regia, not
mercury, to keep them from the Nazis.

http://nobelprize.org/nobel_prizes/medals/ toward the bottom of the
page.

Michelle


#20

All I can say in reply to the you all have shared in
response to my question is WOW! I had no idea., none at all, about
any of that; not the history of the hidden Nobel prizes, not the
chemistry involved, not the gold mining with mercury. It’s like
something out of a science fiction novel! I think I’ll go back to
instructables.com and thank the poster of the original comment. Then
I’ll point him.to this thread on Ganoksin so he can read it too.

Once again I stand humbled in the presence of so many who know so
much more than I. Thanks, Orchid–y’all rock!

Kathy Johnson
Feathered Gems Jewelry
http://www.featheredgems.com