The BGS mineralogy and petrology collections contain upwards of a million samples, housed at Keyworth and in Edinburgh.
Roughly a quarter of this is prime material arranged into a number of major archive collections, please see the key to alphabetical prefixes for further details.
The petrological thin sections (microscope slides) are being imaged (plane and cross polarized light) and progressively linked to the database. Currently about 100 000 Scottish thin sections are available (S & N registration series). 75 000 English and Welsh thin sections (E registration series) will be added in due course.

The database contains over 200 000 entries and includes most of the prime material. The information has been accumulated over many years from variable sources and it contains some inconsistencies and imperfections. Feedback on these is welcomed and should be directed to Mike Howe.