An ingot of copper metal, made by smelting copper ore in vessels in a pit kiln. The smelted metal can then be poured into molds, which when sufficiently cooled, produce ingots. It is the first tier of metal possible in TerraFirmaCraft (although you can smelt the next tier metal, you cannot weld it without making a copper anvil first).
Copper ingots can be welded on top of raw blocks of igneous stone, thus not requiring an anvil to make double ingots. To make a copper anvil, combine 7 double ingots on a crafting bench. The copper anvil then allows you to weld ingots of the next tier, and so on and so forth.