Organized by chemical composition. Photos are above average typically two minerals per page. Only one photo of each mineral type. Good supply of typical mineral data, with a drawing of crystal structure for each mineral. The rock photos are excellent.
Photos are good for gemstones, and there are often two or more for any given material.
The physical property data takes up about 1 page on average for a mineral type, and then often several more pages describing characteristics of type members. Data includes optical properties. Synthetics are covered at the rear of the book. 450 color photos and more than 100 gemstone materials are covered.