There are currently two main methods used for scientific authentication of ceramics:
Scientific Authentication of Antique Ceramics
Most authentication of antique Chinese porcelain and pottery is
currently done by visual inspection, which not only requires a vast
knowledge but also many years of experience.
Scientific methods are available but not widely used. Partially this could be due to the relatively high cost involved. It may not always be a good idea to do a scientific analysis costing more than the item itself.
Thermoluminescence dating (TL dating) is more suited for pottery than porcelain. It requires the removal of fairly large clay samples of approx. 3 mm diameter, which may destruct thin porcelain. Here is a link to Oxford Authentication Ltd. , which currently probably is the world's foremost provider of TL analysis. See principle of TL dating
Other scientific methods are based mainly on elemental analysis of the present elements, execute with the help of spectroscopy (spectrometric analysis). With this method the sampling amount is so minute, that it is invisible to the bare eye. That makes it more suitable for the finer porcelains.
One method, specifically, seems to be getting more popular: Laser Ablation Mass Spectrometry
Spectroscopy (or spectrometric analysis) is not a new testing method in material identification. In different forms it has been employed for decades by the industry for the examination of material composition, as for example with metals.
With spectroscopy the trace elements present present in the clay or glaze of antique ceramics can be analyzed and the results are then compared to sample data from the different kiln sites and periods.
Once they fit, the period and location of production of a ceramic item is positiviely identified.
See more about element analysis and spectroscopy
Download introduction to Laser Ablation ICP-MS (courtesy E. Bartle)
In future this type of scientific authentication is likely to gain popularity for porcelains due to its non-destructive sampling. The extracted amount of material is extremely small and doesn't harm the ceramic body.
There are rumours that expert forgers are catching up on spectrometry analysis methods too and are now sometimes adding the necessary mineral elements to the clay to fool the instruments. Thus, we may not be able to completely rely on this method alone in the future either.
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Antique Porcelain Appraisal
Spectrometry and its use with antique ceramics