An optical material including a crystalline silicon and FexSi2 in the form of dots, islands, or a film is provided. The FexSi2 has a symmetrical monoclinic crystalline structure belonging to the P21/c space group and is synthesized at the surface or in the interior of the crystalline silicon. The monoclinic structure corresponds to a deformed structure of &bgr;-FeSi2 generated by heteroepitaxial stress between the {110} plane of the FexSi2 and the {111} plane of the crystalline silicon. The value of x is 0.85≦x≦1.1. An optical element using the optical material is also provided.