Etched cleavage plane of gypsum (var. selenite) as seen by atomic force microscopy. The true height of the surface is represented using a false-color table inspired by the sequence of colors in an oil slick. Regions of uniform color are atomically smooth terraces, separated by lattice steps 0.7 nm tall. Dots on the terraces are islands deposited from the etching solution. The area shown is a 14µm x 14µm square (about 1/4 of the diameter of a human hair). The full scale of the color table, from black to pink, is about 6nm - twice the diameter of a DNA double helix. Imaged with the Cypher AFM.