Frei: Tantalum is an element – like a pure element. And I think if you can work with nature’s pure elements, one that you can find in the periodic table, that’s a great thing. It hasn’t been used often, obviously, because it’s a material that eats the drill bits. It is very difficult to machine and not because it’s particularly hard – it is hard – but it is kind of … sticky.

So this is actually the problematic thing about it. But what you have is this pure, beautiful dark metal. Tantalum is a very dark metal, it’s a very dark, violet-blue color. Aesthetically, it can’t be beat – not with any coating. It’s the beauty of the material that somehow makes me want to use it again, even though it’s forbidden.