Abstract The engravings on Harappan stamp seals allow the identification of particular artisans in the past. Toward this end, this article employs three-dimensional optical microscopy of stamp seal engravings to provide a non-destructive source of data for reconstructing specific sequences of action. Comparing these operational sequences ( chaines operatoire ) reveals similarities that probably resulted from past production events undertaken by differing individual carvers. Applying this high resolution approach to a sample of five unicorn stamp seals from Mohenjo-daro (2600–1900 B.C.) strongly suggests that their engravings are the work of three artisans. The differences in their operational sequences provide preliminary insights into the boundaries between the communities of practice that produced Harappan seals. This approach can extend archaeological inquiry into many aspects of the social conditions in which seal production occurred. A close analysis of operational sequences reveals how the traces of specific actions, faithfully recorded in stone, can help us find people in the past whose specific activities would otherwise lie outside of scholarly investigation.