Launched in 1962, the Rado DiaStar made history as the world's first scratch-resistant watch. Made from tungsten carbide, a material ten times harder than steel, it was previously used mainly in industrial tools. It was one of the first watches to feature synthetic sapphire crystal for total scratch resistance. Its massive, futuristic oval shape was dictated by the technical constraints of machining hard metal, immediately becoming its aesthetic signature. The DiaStar's design has remained virtually unchanged for six decades, retaining its imposing case and rotating anchor on the dial (symbolizing automatic movements).