My Tungsten Cube (2019)

Apparently tungsten is what forgers use to (fraudulently) pad gold bars. Its mass is pretty close, so it takes something similar to a ground penetrating radar to detect that it is fake, unless you drill or cut it.

I guess a side effect is that you instinctively know what the weight of that size of a piece of gold feels like. A piece of gilded lead or iron the same size won't weigh in enough to convince you. But a piece of gilded tungsten? Not so obvious, apparently.