Refractive index of Al$_3$C$_2$B$_{48}$ aluminum borocarbide crystals

Aluminum borocarbide single crystals have been grown from an Al-based solution melt. The crystal lattice parameters have been determined, the dispersion of the refractive index in a 0.55–1.3 $\mu$m wavelength interval has been studied, and the temperature coefficient of the refractive index in a 300–600 K range has been measured. The crystals are characterized by a high refractive index in the visible spectral range in combination with at a high hardness, which makes them of interest for jewelry, as well as for both traditional and X-ray optics.