The earliest metal used by human beings should be meteorite (natural iron meteorite), which was obtained directly from nature at that time and had better performance than stone.

Because at that time, the collection and smelting level of primitive humans had not reached the level of smelting and purifying metal crystals and even alloys.

As for red copper (blunt copper) or bronze, it is recorded in historical materials that the so-called "the earliest metal used by human beings."