Mercury does some strange things. One of the oddest things it does is alloy with other metals- usually non-ferrous metals like gold, copper, aluminum, silver, etc. The strange part of it is it does this at room temperature.
I bought what I thought was gold leaf at a crafts store. I had never bought it before and it came in an envelope and the information on the package was really poor. I had no idea how much I was actually buying. Maybe a few square inches for the $10 I paid for it? Who knows.
I opened up the package and inside were 18 individual sheets of the leaf- each measuring around 4x4". The leaf is on sheets of parchment-like paper and the metal is very thin. It's practically all "surface area".
Upon further examination of the package I discovered it was not gold at all, but some sort of copper/zinc composition.
Fortunately, copper AND zinc can be amalgamated with mercury too. So the project isn't a complete loss.
Though it just isn't as cool as using gold.