Metal generally cannot scratch a diamond. The ability of one material to scratch another depends on its relative hardness, a property where diamonds stand at the very top. Understanding why this is the case involves examining the unique atomic structure of diamonds and comparing their hardness to that of various metals.
The Unyielding Nature of Diamond Hardness
Diamonds possess an extraordinary hardness due to their distinct atomic arrangement. Each carbon atom within a diamond is strongly bonded to four other carbon atoms in a repeating tetrahedral lattice structure. These strong covalent bonds, combined with the dense packing of atoms, make the diamond crystal exceptionally rigid and resistant to scratching. This resistance is measured on the Mohs scale of mineral hardness, a qualitative scale ranging from 1 to 10.
On the Mohs scale, diamond holds the highest possible rating of 10, designating it as the hardest known natural substance. Materials higher on the Mohs scale can scratch those lower. In comparison, common metals fall significantly lower on this scale. For example, gold typically ranges from 2.5 to 3, platinum between 3.5 and 4.5, and steel from 4.5 to 7.5. These comparisons illustrate why typical metals are not hard enough to leave a scratch on a diamond’s surface.
Materials That Can Scratch a Diamond
While metals generally cannot scratch a diamond, certain materials are capable of doing so. The most common material that can scratch a diamond is another diamond. This diamond-on-diamond contact is a primary concern in jewelry, as diamonds can easily abrade each other.
Beyond other diamonds, some industrial-grade superhard materials can also scratch a diamond. These include synthetic materials like silicon carbide and cubic boron nitride. Silicon carbide, used in various abrasive applications, typically scores between 9 and 9.5 on the Mohs scale. Cubic boron nitride, which has a similar structure to diamond, is the second-hardest known material, with a Mohs hardness of about 9.5. These materials are specifically engineered for extreme hardness.
Caring for Your Diamond
Understanding a diamond’s exceptional hardness is useful for its proper care. Since diamonds can scratch other diamonds, it is important to store diamond jewelry separately from other pieces. Using individual soft pouches or jewelry boxes with separate, padded compartments helps prevent contact between diamonds and other gemstones. This precaution safeguards not only the diamond but also softer precious metals and gems that could be damaged by a diamond.
Regular cleaning helps maintain a diamond’s brilliance without risking damage. A simple and effective method involves soaking diamond jewelry in warm water mixed with a mild dish soap. After soaking for about 20-30 minutes, gently scrub the diamond with a soft-bristled brush, especially targeting the back of the stone where grime can accumulate. Rinse the piece thoroughly under warm running water and dry it with a soft, lint-free cloth. Avoid using harsh chemicals, abrasive cleaners, or ultrasonic cleaners on certain diamond settings, as these can potentially harm the metal or loosen stones.