lavish cypress
Cold working copper is a practice that can be observed through the start of the chalcolithic period across the globe throughout numerous cultures. It was most prevalent in the great lakes cultures of pre-Columbian north America. The reason it was the main method of metallurgy over smelting is because advanced pottery technology like fire baking clay with kilns, or making crucibles was absent from these groups. This meant that smelting metallurgy was absent from these cultures as well, limiting their metalworking capabilities to native copper, which was abundant in the area.
Mechanics
I believe it would be an interesting addition to incorporate cold working of native copper into some tools like knives, axes, shovels, arrowheads and spearheads. Copper lamellar armor could be made using this method as well, potentially. The mechanic could be similar to knapping or forge splitting mechanics, in terms of integration. A cupstone/stone anvil would be needed for this type of work, alongside some form of hammerstone (could not be used to crack chunks into nuggets). Once the shapes were made, quenching would need to take place in order to turn these tools from brittle metal to softer, more usable tool pieces.
Why?
This brings more mechanics and progression options to the early stages of the game, making copper even more dynamic than it already is, and making early progression accessible in new ways. This would also benefit challenge worlds, and low humidity environments where clay is not common. Most of all, it is a fascinating piece of human history that allowed the progression from stone to initial copper tools. The chalcolithic period of progression is such a short part of vintage story, and I believe it should be more integral towards overall advancements. Often times it can be almost completely skipped, which does not feel right, at least to me.
lofty vault