ockhounds" has never been more popular. Old quarries, road cuts, and exposed landscapes are being examined by new generations of minerals enthusiasts. Each needs a comprehensive guidebook with clear photographs and accurate data. This is it.

In a thick but handy format, more than 700 different minerals and rocks are grouped by color (for ease of location in the book) -- blue, red, yellow, brown, green, white and black crystals; brown and gray sedimentary rocks; and meteorites for anyone lucky enough to find one.

Each has a picture -- four to a page -- opposite detailed but clear data:

• Chemical formula
• Hardness
• Color
• Density
• Lustre
• Cleavage
• Fracture
• Tenacity
• Crystal form
• Similar minerals and where they are likely to occur. And many will have a diagram of its crystal form -- up to four, for fluorite, for example.

The Minerals Encyclopedia is unusual for the number of minerals it covers: more than 700 in 448 pages, with a useful glossary, an introduction to mineral collecting, printed front and back flaps that offer quick reference in the field, and a measuring rule on the back cover. This is a superior reference for rockhounds, geology students and outdoors people with an interest in what's under their feet.