Tantalum

Tantalum is a dense, blue-gray metal that almost nothing can corrode. Anders Gustaf Ekeberg discovered it in 1802 and named it after Tantalus, a figure from Greek myth. It comes mainly from an ore called coltan, mined in Central Africa, Brazil and Australia; mining in war zones has made it a well-known conflict mineral.

In a silicon die, tantalum and tantalum nitride form an ultra-thin lining in every trench before the copper wiring is laid in. Without it, copper atoms would wander into the silicon and ruin the transistors. Tantalum also makes compact, reliable capacitors for phones and laptops, and because the body tolerates it well, it is used in implants and surgical tools.