I loved the Gold Rush unit back in third grade. We went up to the American River and panned for gold, and my panning skills balled above all. I got like three tiny pellets. Of course, it was all fool's gold, aka pyrite, but it was still pretty legit. And this was before wearing gold chains was cool—or not.
Our obsession with gold dates back centuries and with its sudden hike in value, making counterfeit gold is more and more tempting. An ounce of gold is currently valued at $1,661.70 an ounce. That's not too shabby, so counterfeiters go to great lengths to fool potential investors, and you might soon be able to also (not that I condone such a thing).
In order to match the density of gold, he used Tungsten as the core. With the tungsten core placed inside a molding cast, he then poured a molten lead-antimony alloy to form the Twinkie-shaped cast.
With the Tungsten core encased in the lead-antimony alloy, the fake now has a similar weight and feel compared to a real gold bar. Now the only thing left to do is create that gold color.
Since this particular counterfeiting project was on an extremely low budget ($200), Gray decided to cover the bar in an authentic gold leaf.
Of course, someone could scratch off the gold with their fingernail, but purely based off of looks, the fake is 100 percent legit.
If you want to make a truly spot-on fake, you would have to shell out upwards of $15,000 for a two-kilogram bar.
The process would stay mostly the same, but instead of using the lead-antimony alloy to form the cast around the Tungsten core, you would need to use real molten gold. When someone scratches the bar, it would reveal nothing but gold. A buyer would need to drill deep inside the bar to reach the Tungsten core before they realize it's a fake.
So make sure you have the cash and a good escape route.
This is all illegal of course, so this serves more as a precaution. If you know how easy it is to fake gold, you'll be more cautious when you actually buy some. Though, who in the hell can afford a gold bar?!?
For more info on this project, head on over to PopSci for the full Gray Matter rundown. Looking for some more Theodore Gray projects? Check out his bacon-fueled thermal lance, see how he got metal from pepto-bismol tablets, and how to break locks with compressed air.