The definitive resource for mineral collectors, this comprehensive book describes the structural relationships among orthosilicate minerals, known for their hardness and brilliant colors, and the geological conditions that create prized specimens. It is illustrated with nearly 500 structure diagrams, color photos, and electron micrographs that will help collectors appreciate the minerals already in their collection, build a collection with greater depth, and find additional information. A web link allows readers to view the crystal structures in three dimensions for a richer appreciation of their details, and an extensive bibliography includes easily accessible references ranging from foundational literature to reports on current scientific research.