Single-crystal calcium fluoride (CaF2) is an excellent optical material in the infrared range and the ultraviolet range. It is an indispensable substrate material for the 193 and 157 nm wavelength laser optics for future large-scale semiconductor photolithography systems. Due to its delicate nature, for the most part the CaF2 elements have been fabricated using conventional pitch polishing combined with interferometry and local surface correction to form the desired flat, sphere or aspherical surface. In the present work, the feasibility of generating high quality optical surfaces on CaF2 by single-point diamond turning is examined. The development of this technology may provide the possibility of fabricating aspherical and diffractive optical components in an efficient way. The machining experiments described in this article were done on a high-stiffness, ultraprecision, numerically controlled diamond lathe with a sharply pointed single-crystal diamond tool. The scale of machining was varied from the micrometer level to the nanometer level. It was found that at the micrometer level, machining was significantly affected by the crystal orientation of the workpiece. The crystallographic anisotropy causes nonuniformity of the finished surface texture, microfracture topography and brittle-ductile transition boundary conditions. The results also indicate that by controlling the undeformed chip thickness below a critical value, namely, the minimum critical chip thickness (85 nm), a uniformly ductile-machined surface could be produced. Under the present experimental conditions, a surface with a maximum height (Ry) of 18.5 nm and arithmetical mean roughness (Ra) of 3.3 nm was obtained. (C) 2004 American Vacuum Society.