Glossary Metals, materials and technology
Slag
The glassy waste left when ore is smelted: the rock and impurities that separate from the molten metal in the furnace.
Slag is the most durable evidence that metal was produced at a site, since furnaces collapse and crucibles break but slag survives in heaps. Its texture also records how well the process worked. Middle Cypriot slag is small and irregular and had to be crushed by hand to pick out trapped droplets of copper; Late Cypriot furnaces ran hot enough for liquid slag to be tapped off in large flat cakes.
The great slag heaps that still mark the Troodos foothills, some four million tons in all, are mostly much later than the Bronze Age. Radiocarbon dates from them fall between about 500 BCE and 500 CE, so Bronze Age slag is scarce and scattered by comparison.
Full entry: Copper Metallurgy in Ancient Cyprus
Related terms
- Smelting
Heating ore with a fuel such as charcoal until the metal separates from the rock, leaving a waste called slag behind.
- Tuyère
A clay nozzle set into the wall or top of a furnace so that air from bellows can be blown into the fire to raise its heat.
- Ore
Rock containing enough metal to be worth mining and smelting; Cypriot copper ore is mostly chalcopyrite, a copper-iron sulphide.