A plasma computer numerically controlled (CNC) cutting machine is controlled by a computer such as a personal computer capable running an operating system and software programs. In an embodiment, the computer executes a CNC program to control movement of a plasma torch to cut parts from a workpiece while a spectrometer determines an emissions spectra of light emitted as the torch cuts the workpiece. The spectrometer cooperates with software running on a computer to analyze the metal as it is being cut by the CNC cutting machine and determine a composition. In embodiments, the composition is compared to an expected composition and saved in a database with identifying information; in a particular embodiment the database is queried to provide identifying information of metal having similar composition to the workpiece.