Copper ingots are standard bars of refined copper, cast after copper ore has been crushed, smelted and cleared of slag. Their regular shape makes the metal easier to stack, weigh and transport than loose ore or scrap. A sound ingot has an even reddish surface; bubbles, cracks or dark inclusions betray poor refining.
Merchants sell ingots to smiths, founders and mint workers, who remelt them for vessels, fittings and coinage. They also provide a convenient measured base for producing bronze and brass. Copper is soft enough to mark or bend at an exposed edge, so valuable shipments are usually crated rather than carried loose.