When it comes to the hardest materials on Earth, diamonds are often the first that come to mind, celebrated for their unmatched natural hardness and durability. However, in the world of materials science, another contender plays a crucial role in various industrial applications: cubic boron nitride (cBN) . This raises a compelling question: Is cubic boron nitride harder than diamond? Understanding Hardness and Material Science Hardness, in materials science, refers to a material's resistance to deformation, particularly permanent changes such as indentation or scratching. The hardness of a material is a crucial factor in its application, especially when it comes to cutting, grinding, and drilling technologies. Diamond: The Unsurpassed Natural Material Diamond, a crystalline form of carbon, has long been recognized as the hardest known natural material. Its extraordinary hardness makes it ideal for a wide range of applications, from jewelry to industrial cutting and drilling tools.