It is an absolute dating method, and does not depend on comparison with similar objects (as does obsidian hydration dating, for example). The thermoluminescence technique is the only physical means of determining the absolute age of pottery presently available.Much stoneware is not so hard as porcelain and may be sampled by drilling.
A leaflet from Daybreak describing the TL technique in more detail and giving a bibliography will be provided to interested persons.
The phenomenon of thermoluminescence was first described by the English chemist Robert Boyle in 1663.
Drilling, the usual method of sampling, introduces some uncertainty.
It is also rare that any information about the radiation from the burial soil can be obtained, as art objects are usually thoroughly cleaned.
This radiation may in some cases contribute over half the total dose.
Finally, one has to make the measurements regardless of whether the TL of the clay is well-behaved or not.
Some of these are quite easy to detect; some quite difficult.
For example figures, normally modeled, may be carved out of brick or assembled out of fragments.
By comparing this light output with that produced by known doses of radiation, the amount of radiation absorbed by the material may be found.