[Orange1998]

Tungsten (W) is a very rare element (one gram of rock contains only about one ten-millionth of a gram of tungsten)

I guess this blows the theory all the gold in Ft Knox is Tungsten. Also found this on wiki.

Because of tungsten's high melting point, it is not commercially feasible to cast tungsten ingots.

[Skepolitic]

“Because of tungsten’s high melting point, it is not commercially feasible to cast tungsten ingots.”

Leaving aside the Ft Know theory, it is indeed commercially feasible to cast tungsten ingots if they can be passed off as gold. This outfit offers tungsten ingot for sale: http://www.americanelements.com/wmi.html. With today’s high gold prices, jewelers are even manufacturing tungsten jewelry.

[Smokin' Joe]

Tungsten is common enough to use as filaments in incandescent light bulbs.

As for Because of tungsten's high melting point, it is not commercially feasible to cast tungsten ingots.

It wouldn't be--if they were valued as tungsten. If you're getting gold prices, though, it's a shoo-in.