A dating technique applicable to pottery and other ceramic materials. It works on the principle that all matter is constantly bombarded by cosmic rays and radiation given off from the decay of radioactive elements in the ground and in objects themselves. Minerals that are bombarded in this way by radiation build up a store of energy within their crystalline structure which is released when heated. The longer or more intense the bombardment, the more energy is stored and thus the more there is to be released. When a piece of pottery is fired, all the previously stored energy is released and the build‐up starts afresh. After excavation a shard can be heated again and its stored energy released and measured. If the level and extent of bombardment to which the pottery has been exposed while buried is known (the dose rate), or can be estimated, then the age of a sample can be calculated in terms of the time that has elapsed since it was last heated. The range of the technique is potentially unlimited, but it has an accuracy of ± 5–10 per cent.