Do you recognize the harbour in this painting? No, you probably don't, because it's not a painting at all, but the natural colouring on a section of polished paesina stone. This image, along with countless other artistic pictures of minerals and rock formations, can be found in Exposures of Mineral and Rock by Dirk J. Wiersma (Inmerc bv, €49.50). This coffee-table book, which has text in both Dutch and English, is a stunningly illustrated guide to rocks, crystals, geodes, gems, fossils, minerals and all manner of things geological.