There is an alternate Earth that I've been building and rebuilding for years. The canonized point of departure is 56 million years ago, specifically a Paleocene-Eocene Thermal Maximum that is four to five times longer than in our timeline. So the sophont primates of this alternate Earth, the elves, aren't simians but "xenosimians" of the family Allopithecidae, not Hominidae. Nevertheless, they shared some historical parallels, right down to the interbreeding with the dwarves and a mysterious "Third Race".
Long ago, I asked a question regarding the construction of metal weapons without the use of iron at all. In the answers selection, many candidates have been suggested, and they are:
- Titanium Alumnide
- Nickel Superalloy
- Nickel Alumnide
- Tungsten Carbide
- Zirconium Carbide
- An alloy of Titanium and Tungsten
These are all compelling choices, and ones that would make elvish stonemasonry, weaponry, armory and later construction stand out from those in humanity's time. But the real life problem with those materials is scarcity. There might not be enough for any of them in the world to forge weapons and armor on countless armies of soldiers.
So, in possible lieu of the materials listed above, there has to be a more common, more readily available metal for post-Bronze Age elves to extract and use for defensive, masonry and constructive purposes. Metal that, used on a soldier, would be lighter than iron, stronger than iron and able to delay the rusting process by many, many centuries. Metal that, in constructing a skyscraper, would be lighter than human steel, stronger than human steel and able to delay the rusting process by many, many centuries.
But could such a metal have formed naturally on this alternate Earth at a maximum date limit of 56 million years?