A tool management system utilizes an optically readable indicia to identify tools. The indicia comprises a pattern (180) having pattern elements which are geometrically similar in shape. The pattern elements, which may comprise rings, are sized and positioned to identify characteristics of a tool (110) to which the pattern is applied. Each pattern element is disposed within a predetermined zone, and in the preferred embodiment, the boundaries of each pattern element are compared to the midpoint of the zone to decode the pattern. While the indicia is preferably used in connection with tools, it has application to other objects, and it is particularly advantageous where a relatively large amount of information must be encoded.