Pyritohedron Small 320×278 Medium 640×557 Large 1024×891 Download TIFF Original 2400×2088 | (326.2 KB) Description "This form consists of twelve pentagonal-shaped faces, each of which intersects one crystallographic axis at unity, the second axis at some multiple, and is parallel to the third." — Ford, 1912 Keywords geology, geometry, pentagon, pyritohedron Galleries Dodecahedrons Source: William E. Ford Dana's Manual of Mineralogy (New York: John Wiley and Sons, Inc, 1912) 25