  Despite its unrivaled hardness, diamond can be severely worn during the
interaction with others, even softer materials. In this work, we calculate from
first-principles the energy and forces necessary to induce the atomistic wear
of diamond, and compare them for different surface orientations and passivation
by oxygen, hydrogen, and water fragments. The primary mechanism of wear is
identified as the detachment of carbon chains. This is particularly true for
oxidized diamond and diamond interacting with silica. A very interesting result
concerns the role of stress, which reveals that compressive stresses can highly
favor wear, making it even energetically favorable.
