I must be misunderstanding. This is the same answer I see posted to the question when I search via google.
I have farmed some 'COPPER FRAGMENT' (Orange/red crystal) and some 'ZINC FRAGMENT' but putting it in the forge didn't do anything/none of the forges have 'copper/zinc' counters. I can't grind it either as there's no recipes?
I can scrap the copper fragment into 'COPPER' which looks like some copper wire. This item also has no recipes.
I've hit tungsten/lead at the bottom of the map, but I get all my brass from picking through garbage and salvaging.