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Low‐energy electron diffraction (LEED) and Auger electron spectroscopy (AES) have been used to characterize a range of silicon surfaces with orientations along the azimuth from (001) to (111). Both clean and carbon‐contaminated surfaces have been studied. When clean, no faceting of these surfaces is observed, even after prolonged annealing. Following annealing above 950 °C, however, carbon contaminated surfaces oriented between (111) and (113) facet to expose (111) and (113) surfaces. Carbon‐contaminated singular and vicinal Si(001) surfaces facet to expose four {113} facets. The clean Si(113) surface is reconstructed: the same reconstruction also appears on the {113} regions of the faceted surfaces. The (111) regions of the faceted surfaces also show the clean‐surface 7×7 reconstruction. The faceting can be induced by as little as 0.3% of carbon on Si(112) but 3% carbon is required before faceting is observable on Si(113). Optical microscope images of the surfaces reveal pits up to several microns in width, with well‐defined shapes matching the facet orientation measured by LEED. Equilibrium and kinetic mechanisms for the faceting are discussed.