A team of volunteers have spent the past year photographing over 100,000 thin sections, in both plain polarised (PPL) and cross polarised light (XPL), and the collection will soon be available to the public, to view online.
A blog maintained by BGS staff records the details of this impressive feat. This is not the end of monumental task- the volunteers will now be moving onto the collection of 11,000 thin sections from Scotland and Northern England.
The BGS rock collection (mineralogy and petrology database) can be found here.