Runite Ore

You might be surprised to hear that runite, as an ore, is soft. Like gold it is easily marked. Thank our ancestors that they didn't immediately toss the ore into a bin, though. They tinkered with alloys, working with luminite ore in the combustion process to create something remarkable.

You can see why they persisted. Runite ore has some funky properties - repelling materials, occasionally floating, spinning when you sing to it - that makes it an ore with clear potential.