Psychometry was the ability to sense the impression of past events, thoughts or emotions: the stronger the emotion, the clearer the psychic impression. Traditionally, people using psychometry touched an object and had an image of the past of that object come into their mind. It had something of the quality of time travel. Barbara Wright described it as "an improvement of fingerprints," as the people of Millennius used psychometric tests in their investigations.
Professor Herbert Clegg demonstrated his psychic powers for the Third Doctor by using psychometry (called psycholotry by the Doctor) on the sonic screwdriver and a crystal taken from Metebelis III. In the former instance he saw Drashigs. With the latter, the images of the Eight Legs frightened Clegg so much that he died of heart failure. He showed the Doctor these images through use of an Image Reproduction Integrating System. (TV: Planet of the Spiders)
Silverman was a psychometrist. Bart Addison took Mykloz to Silverman to find out who he was by the objects in his pocket. Although the objects seemed to indicate that Mykloz was the Seventh Doctor, Addison deduced that he was not. (PROSE: Playback)
Most of the commerce on Tiaanamat was done using psychometric objects. For example, Clara bought a moped from Dor'een using a ring from her mother, since she had strong memories of her. Psychometric offerings were also given to the Old God during the Festival of Offerings. (TV: The Rings of Akhaten)