WE walk on jewels. And in few places more so than Cornwall, where mining and quarrying have revealed breathtakingly beautiful rocks and minerals.

The latest in the 'pocket' series of books from Cornish publishers Alison Hodge homes in on the subject.

Author Simon Camm first became fascinated when he came across a man-made grotto lined with mineral crystals. It fired his passion for them and after a career as a geologist and consultant he is now a Fellow of the Royal Geographical Society of London.

But you don't have to be a geologist to be fascinated by this book. In it, Camm divides Cornwall into eleven districts, stretching from Land's End to the Tamar. Images of minerals found in each are shown in photographs, making for a colourful and at times bizarrely beautiful collection.

Some, such as mimetite and pyromorphite with their almost sea-bed-like appearance, are in stark contrast to the sharp, silver lines of chalcocite and cassiterite, shown on the same page. Similar pieces, such as apatite with quartz, where a sheer piece stands upright amid what looks like a foaming sea, appear to be works of natural art.

Near to home, Old Gunnislake Mine produced a green, secondary uranium mineral metatorbernite, in well crystallised specimens. And at Hingston Down Mine, the apple-green mineral arthurite was once abundant on old spoil tips, Camm writes.

But it is not just the glittering geological prizes that catch the eye in this book. A photograph of a pebble on Marazion Beach shows a perfectly formed, reddish oval, inlaid with grains of white and green. Nature's Faberge egg.

l Cornish Rocks and Minerals by Simon Camm is published by Alison Hodge Publishers, price £5.95.

COLIN BRENT