A highly wear resistant sintered, hot pressed, or otherwise compacted ceramic composite material is described, consisting of two discrete phases of the form Al_xMg_yB₁₄ where x and y ≦1 or like hard, orthorhombic compounds, and TiB₂ or like Group IVB transition metal di-borides, and with an unexpectedly high contentof transition metal di-boride in the range from 40 to 90 percent (28 to 85 volume percent).