First order prism Small 158×320 Medium 315×640 Large 505×1024 Download Tiff Original 1183×2400 | (212.8 KB) Description "The prism of the first order consists of four rectangular vertical faces, each of which intersects the two horizontal crystallographic axes equally." — Ford, 1912 Keywords first, geology, geometry, order, prism, rectangle Galleries Prisms Source: William E. Ford Dana's Manual of Mineralogy (New York: John Wiley and Sons, Inc, 1912) 32
