Diamonds are often considered indestructible due to their renowned hardness. This common perception, however, overlooks the complex interplay of a diamond’s atomic structure and the specific forces that can cause it to break. While diamonds are exceptionally hard, their response to a sudden, sharp impact, such as from a hammer, involves different scientific principles than their resistance to scratching. Understanding these properties reveals that a diamond’s interaction with force is more intricate than simply being “unbreakable.”
Understanding Diamond’s Strengths
Diamonds are the hardest natural material on Earth, a property describing their remarkable resistance to scratching or abrasion. This characteristic stems from their unique crystal lattice structure, where each carbon atom is bonded to four others in a strong, three-dimensional arrangement. This robust atomic bonding requires substantial energy to disrupt, making it incredibly difficult to scratch a diamond. This exceptional hardness is why diamonds are used in industrial applications for cutting and grinding.
Hardness is distinct from toughness, which refers to a material’s resistance to fracturing or breaking under impact. While diamonds excel in hardness, they are not inherently tough and are considered brittle. Their crystalline structure contains specific planes of weakness, known as cleavage planes. Along these planes, the atomic bonds are slightly weaker and more susceptible to separation when sufficient force is applied. This means that while a diamond resists scratching, a sharp blow can cause it to split or shatter.
The Science of Force and Fracture
Materials break when the internal forces holding their atoms together are overcome by an external force. When an object, like a hammer, strikes a material, it imparts kinetic energy, creating localized stress within the material. If the applied stress exceeds the material’s inherent strength, those bonds will break, leading to fracture.
The manner in which a material fractures depends on its internal structure. In crystalline materials like diamonds, atoms are arranged in a highly ordered, repeating pattern. This arrangement means that there are specific directions, or cleavage planes, where atomic bonds are weaker. When a force is applied precisely along one of these planes, the material is more likely to cleave cleanly along that path.
When a Hammer Strikes a Diamond
Given a diamond’s unique combination of extreme hardness and inherent brittleness, a hammer can indeed break a diamond. If a diamond is struck with enough force and, crucially, if that force is directed along one of its cleavage planes, it can fracture or even shatter. Breaking a diamond requires overcoming the atomic bonds along these specific structural weaknesses within its crystal lattice. The impact from a hammer provides the concentrated energy needed to exploit these planes.
This susceptibility to impact is well understood in the diamond industry. Diamond cutters, for instance, utilize a process called cleaving, where they strategically strike a diamond along a cleavage plane to split it into smaller, more manageable pieces. This precision allows them to shape rough diamonds without resorting to grinding away material. Therefore, while a diamond will resist scratching by nearly any material, a targeted, forceful blow can overcome its structural integrity and cause it to break. This explains why diamonds can be damaged by sharp impacts in jewelry settings.