This book explains the structural relationships among di- and ring silicate minerals, known for their hardness and brilliant colors, and the geological conditions that create the beautiful crystals prized by collectors. The minerals are arranged systematically to emphasize how they fit into structural groups, and generously illustrated with nearly 600 structure diagrams, color photos, and drawings. An extensive bibliography includes a broad range of easily accessible references ranging from the foundational literature and original species descriptions to reports on current scientific research.