This is the ultimate photographic guide to all types of rock, an essential reference book for even the most experienced geologist, with many tips on sourcing rocks in the field and identifying collected specimens. The first part of the book will give amateurs and enthusiasts a thorough grounding in how rocks are made.The second part is a photographic directory of 150 different rocks, grouped by major categories and composition. It covers such ancient rocks as greenstone, rare rocks like eclogite, pegmatites - prized for their beauty - and much more. Practical information and checklists to aid classification make this the perfect fieldbook.