Abstract: A durable part marking is achieved by local surface material modification. Selected surface area properties of the part are altered without substantial alteration of the physical configuration of the part. The alterations are placed in a coherent pattern accomplishing a durable method of identification marking on a part. Subsequently, the coherent pattern is detected and the coherent pattern interpreted to retrieve the original identification marking. Unlike labeling, ink marking, stamping or etching, many surface or near-surface modifications are not necessarily visible to the human eye. Hence, the invention includes: 1) a method for surface modification, 2) a method for assuring enhanced readability and accuracy of the read back of the encoded data, and 3) a method for locating the surface alteration.