Tungsten carbide (WC) is one of the hardest engineered materials in existence, renowned for its exceptional durability and resistance to wear. This compound, formed by bonding tungsten and carbon atoms, has revolutionized industries ranging from manufacturing to jewelry. Its hardness is second only to diamond, making it indispensable for high-stress applications. This article explores the hardness of tungsten carbide, its measurement methods, influencing factors, applications, and comparisons with other materials.