Ashley Cooper / China Clay workings, near St Austell, in Cornwall, England, UK, April.

Graham Eaton / An old mill stone used in the extraction of China Clay (Kaolinite) from rocks near Rhoscolyn, Wales, UK, June.

John Cancalosi / 'Zebra stone', sedimentary rock from the east Kimberley of Western Australia.Composed essentially of small particles of quartz and sericite' (fine-grained white mica), zebra rock also contains the min...