The 'enamel' option refers to the application of black enamel to the university mark engraved on our sterling silver signet rings. This black enamel enhances the definition of the mark and makes it stand out more prominently against the silver. Conversely, the 'natural' option does not include any enamel, offering a more subtle, silver-only appearance of the university mark. The choice between 'enamel' or 'natural' allows for a degree of personal preference in the appearance of your ring.