For an archaeologist digging in the ground, the answer is clear: ceramics last longer. A sword, a helmet, a bowl or a brooch made of metal will rust badly, reacting with chemical substances, including oxygen, water, salts, acids, alkalis and certain gases such as hydrogen sulphide or nitrogen oxides in the soil. Within just a few years, they can be completely gone.
Ceramics, on the other hand, are extremely resistant. It is not uncommon for excavations to unearth vessels that are thousands of years old, which may be slightly cracked, but after careful restoration look as if they have just come out of the pottery. Only in acidic soils does pottery become brittle and susceptible to weathering over time – but by then the metal is long gone.
