It is used by gold "prospectors" and "panners," along with jewelers to recover very small amounts of gold and gold dust. It is also used by those recovering small amounts of gold from gold-plated items and to recover the gold from items that have had "gold leaf" applied. It "amalgamates" gold...it actually disolves gold into itself just like water disolves salt into itself. From what I remember a pound of mercury will "amalgamate" anywhere from 3 to 6 pounds of gold. It is also used in dentistry...it is used in "silver fillings" for cavaties.
Kelly
Ok, a side note on this. As a professional gold assayer over the years I had lots of opportunity to work with mercury amalgam. Please bear in mind I'm not trying to be a "know it all" here, nor to offend anyone, and my apologies if it comes across as such. I'm just relating my own experiences.
Very few things actually dissolve gold, among the best are aqua regia and molten lead. Chlorine solutions, even chlorine bleach, will slowly dissolve gold. But not many other things. Mercury does not dissolve gold but WETS it. If you tried to remove gold leaf from a metallic object all you would accomplish is a mercury-coated gold leaf. Mercury will absorb gold into it's mass, but most everything else will be left floating on top or ignored by it. The tiny bits of gold will actually disappear into the blob of mercury, but they are still the same shape and form within the blob as they were outside. The mercury has had zero effect on the gold particles other than to wet them and absorb them.
When mercury has absorbed all the gold it can hold, it becomes stiff and can be molded like a snowball. It even "squeaks" like wet snow.
50/50 nitric solution is pretty strong to dissolve mercury, but it will work. It's dangerous to drop amalgam into strong hot nitric acid because it will fizz and effervesce, many times boiling over on your hot plate. Best to use a weaker solution and never get it to boiling. And DON'T breathe any red-brown fumes coming off the acid. When the mercury is all dissolved the gold particles are left in the nitric solution, minus any iron or certain other metallic bits that may have been clinging. When cool these can be filtered and washed with distilled water. You will have all the gold that was inside the amalgam.
A safety tip: be extra careful handling nitric acid. It likes to dissolve human tissue with even more relish than mercury. I have numerous scars as proof.
The mercury can be reclaimed from the spent nitric solution by stirring with a copper rod or a piece of bare #8 solid electrical wire.
