Tourmaline Small 164×320 Medium 328×640 Large 525×1024 Download Tiff Original 1230×2400 | (352.5 KB) Description "Tourmaline crystals show the forms of the Rhombohedral Class but with hemispherical development. They are also commonly characterized by the presence of three faces of a triangular prism." — Ford, 1912 Keywords crystal, geology, geometry, mineral, tourmaline Galleries Crystals Source: William E. Ford Dana's Manual of Mineralogy (New York: John Wiley and Sons, Inc, 1912) 44
