To see a chart of where various metals and materials fall on the Rockwell Hardness Scale, navigate to sizes.com/units/hardness_rockwell.htm. The website contains a brief description of the Rockwell Hardness Scale and is followed by a table containing 30 different hardness scales.
The regular Rockwell Hardness Scales comprise 15 different values. Each one has a single letter name, such as "A," and covers the heavier materials such as steel. The Superficial Rockwell Scales comprise another 15 different values, each one having a two-digit number and a letter, such as "15N." These values cover thinner or very soft materials. The table was taken and adapted from "Rockwell Hardness Measurement of Metallic Materials," written by Samuel R. Low.