This article examines efforts by De Beers, the world's largest supplier of rough diamonds, to better regulate the conditions under which its stones are cut and polished across a global network of buyers, contractors, and subcontractors. Drawing on ethnographic fieldwork at an offshore processing unit in South India that was built to service De Beers' buyers, this article explores how ethical accounting regimes are materialized on the floor of a global factory and how they are grounded in an industrial bureaucracy. In a global supply chain like this one, I argue, codes of practice and audit checklists demand to be understood as material technologies that afford companies and individuals new purchase on an ethic of detachment.