Diamonds are legendary for being the hardest natural substance on Earth. This extreme durability often leads people to believe the stone is completely indestructible, but this perception is inaccurate. While diamonds are exceptionally resistant to surface wear and scratching, their crystal structure contains specific vulnerabilities. Understanding the true nature of a diamond’s durability reveals that this gem is not impervious to all forms of damage.
Understanding Diamond Hardness
The definitive answer to whether a diamond can get scratched lies in the scientific measurement of its hardness. Hardness refers to a material’s resistance to surface abrasion, quantified using the Mohs scale of mineral hardness. Diamonds achieve the maximum rating of 10 because of their unique atomic structure. Each carbon atom is tightly bonded to four others in an extremely rigid, three-dimensional lattice.
This strong structure means that only another material of equal or greater hardness can scratch a diamond’s surface. Practically, this means only another diamond or highly specialized industrial abrasives can cause surface damage. Most common materials encountered daily, such as glass, metals, or dust, are far softer and will not cause surface scratches.
The abrasive grit in household dust is often composed of minerals like quartz, which scores a 7 on the Mohs scale. While these particles can scratch softer gemstones, they are no match for the diamond’s superior hardness. However, surface damage can occur if one diamond rubs directly against another. This diamond-on-diamond contact is the most common way a scratch appears on a finished gem.
The Difference Between Hardness and Toughness
The common confusion about a diamond’s durability stems from conflating “hardness” with “toughness,” which are two distinct physical properties. Hardness is the resistance to scratching, but toughness is a material’s ability to resist breaking, chipping, or fracturing when subjected to a sharp impact. Though diamonds are the hardest known substance, their toughness is only rated as moderate, making them somewhat brittle.
A diamond’s crystalline structure, which gives it its extreme hardness, also contains specific planes of weakness called crystallographic cleavage planes. These are four specific directions within the crystal lattice where the atomic bonds are slightly weaker. A sharp, forceful impact delivered precisely along one of these cleavage planes can cause the diamond to chip or split entirely, despite its scratch resistance.
This vulnerability is similar to how a piece of very hard glass can still be easily shattered with a sudden blow. The diamond cutter utilizes these planes of weakness to cleave a rough stone during the cutting process. For the wearer, an accidental strike against a hard surface, such as a granite countertop, can potentially cause a chip, especially on exposed points, corners, or a thin girdle.
Avoiding Damage and Proper Care
Protecting a diamond requires mindful handling based on its specific vulnerabilities to impact and abrasion. Because a diamond can only be scratched by another diamond, it is important to store diamond jewelry separately from other pieces. A fabric-lined jewelry box or a soft pouch for each item will prevent stones from rubbing against one another and causing surface damage.
It is also advisable to remove diamond jewelry before engaging in strenuous activities, such as gardening, intense sports, or heavy housework. These activities increase the risk of a sharp blow that could exploit a cleavage plane and cause a chip. Diamonds also attract grease and oils easily, which can dull their brilliance over time.
To maintain the stone’s sparkle, regular cleaning should be performed using warm water and a small amount of mild dish soap. A soft-bristled toothbrush can gently scrub behind the stone to remove accumulated dirt and oils. Furthermore, avoid exposing the stone to harsh chemicals like chlorine bleach. While the diamond itself is chemically stable, these substances can damage the metal setting, potentially loosening the stone.