it is made of metals irons bronze and gold at metal age
Copper came first, and then tin, and then bronze, a combination of the two. These metals were put into a kiln ( a simple oven) as rocks, and then the metal came out because the kiln was hot. This was much hotter than what you would get over a campfire. The creation of the kiln came about for making pottery, which is also useful. Most likely the metal that flowed out of the rocks was collected in a bowl of some sort ( some sort of pottery). Soft metals such as copper could then hammered with rocks for example to form tools such as a knife or a spear tip.