Sphalerite Small 320×311 Medium 640×622 Large 1024×995 Download TIFF Original 2400×2332 | (537.4 KB) Description "Isometric; tetrahedral. Tetrahedron form." — Ford, 1912 Keywords crystal, geology, geometry, isometric, mineral, sphalerite, tetrahedron Galleries Crystals Source: William E. Ford Dana's Manual of Mineralogy (New York: John Wiley and Sons, Inc, 1912) 142