There are many more techniques employed to discover fakes and forgeries, I have summarized some of them here and hope to create pages for each of them in the future.
Exposing an object to ultraviolet light can reveal many things that are invisible in normal light. UV light causes some organic chemicals to fluoresce (give out visible light). This is particularly useful when looking to see if there are any repairs as glue and binding agents usually show up under UV light. It can also be used to see if there has been any repainting or touching up and can even reveal ink invisible to the naked eye.
Scanning Electron Microscopy
This comes into its own when the analysis of a very small area is required. For instance it could be used to examine brush strokes on a painting or look for the markings of a tool used. Scanning electron microscopy has been used to examine the blood stains on the Turin Shroud.
Mass spectrometry can be incorporated into many analytical techniques and is used in radiocarbon dating. One particular use is identifying the origins of white marble. White marble is virtually indistinguishable to the naked eye and also chemically very pure. Marble is a calcium carbonate and contains both carbon and oxygen. The ratio of either carbon or oxygen isotopes can identify where a marble was quarried from as different quarries have characteristic ratios. This method can also identify different types of marble used in the same piece, indicating that a repair has been made.
This is another dating technique which is particularly useful for dating ceramics. It works on the principle that crystalline materials which have been exposed to ionizing radiation, e.g. alpha, beta and gamma rays, will emit light when they are subsequently heated. This requires a heat of above 350°C. The longer the object has been exposed to radiation, the more light it will emit, therefore the amount of thermoluminescence corresponds to the age of the object.