Wolfram carbide is black hexagonal, with metallic luster. Its hardness is similar to diamond. It is good electricity  and heat conductor. . Wofram carbide does not dissolve in water, hydrochloric acid and sulfuric acid, but wolfram carbide is soluble in nitric acid - hydrofluoric acid mixture. Pure tungsten carbide is fragile, if mixed with a small amount of titanium, cobalt and other metals, the  fragile can be reduced. The tungsten carbide cutting tools for steel, often adding titanium carbide, tantalum carbide or their mixtures, in order to enhance antiknock capability.