JEWELRY EDUCATION
Toughness vs Hardness: Can a Diamond Break?
Diamonds have long been associated with strength, often described as the hardest natural substance on Earth. Even though it’s true that diamonds rank 10 on the Mohs hardness scale – making them highly resistant to scratching – they are not indestructible.
In understanding a diamond’s durability, it’s important to know the distinction between hardness and toughness. These are two very different properties that affect how a diamond withstands wear and impact.
In this article, we’ll discuss what makes a diamond so hard, why it can still break or chip under the right conditions, and how to properly care for and protect your diamond jewelry.
Hardness vs. Toughness: What’s the Difference?
Hardness and toughness are often used interchangeably, but they describe distinct characteristics of a gemstone:
- Hardness refers to a material’s resistance to scratching. Diamonds are the hardest known natural material, meaning nothing except another diamond can scratch them.
- Toughness refers to a material’s ability to resist breaking, chipping, or fracturing when struck.
While diamonds are hard, they are not the toughest material and can still break if subjected to a sharp impact. For instance, even though diamonds are harder than jade stones, they are less tough; this means that Jade stones are less susceptible to breaking than diamonds.
As another analogy, consider a piece of glass and a piece of steel:
- Glass is very hard (resistant to scratching) but not tough (it shatters easily).
- Steel is less hard (can be scratched by certain materials) but very tough (it bends rather than breaks).
- Diamonds are extremely hard but have moderate toughness, making them vulnerable to sharp impacts.
Why Can a Diamond Break?
Even though they’re the hardest substance on earth, diamonds have a crystalline structure with “natural planes of weakness”. These planes are known as cleavage planes. If hit at just the right angle with enough force, a diamond can chip, crack, or even split along these planes.
Common Causes of Diamond Breakage or Chipping:
- Hard Impact – A sharp blow against a hard surface (such as hitting a countertop, dropping a ring, or knocking against a metal object) can cause a diamond to chip or break.
- Thin or Pointed Edges – Certain diamond shapes, like marquise, pear, and princess cuts, have sharper edges and pointed corners that make them more prone to being damaged
- Flaws or Inclusions – Diamonds with large inclusions, fractures, or structural weaknesses are more likely to break under stress.
- Improper Settings – A poorly designed setting that doesn’t provide adequate protection (such as an exposed prong or tension setting) can leave the diamond vulnerable to impact.
While round brilliant diamonds are the most durable due to their lack of sharp edges, other shapes may require extra care and protective settings to minimize the risk of damage.
Which Diamond Shapes Are More Prone to Chipping?
Certain diamond shapes are more fragile than others due to their design and structural points of weakness.
More Susceptible to Chipping or Breakage:
- Princess Cut – Sharp, 90-degree corners can chip if struck.
- Marquise, Pear, and Heart Shapes – Their pointed tips are vulnerable to impact.
- Emerald and Asscher Cuts – Large, open facets expose inclusions and may increase the risk of breakage if not well-protected.
More Durable Diamond Shapes:
- Round Brilliant – Lacks sharp corners and has excellent structural
- integrity.Oval and Cushion Cuts – Softer, rounded edges reduce the risk of chipping.
For fragile diamond shapes, choosing a bezel or V-prong setting can provide extra protection.
How to Protect Your Diamond from Chipping or Breaking
Even though diamonds are super durable and have supreme hardness, it’s important to take a few precautions to help preserve their beauty and longevity:
1. Choose the Right Setting
Certain settings place the diamonds in a more “safe” placement than others.
- Bezel settings fully encase the diamond, offering the highest level of protection.
- V-prong settings, where the prongs cover the corners of the diamond, are ideal for pointed shapes (marquise, pear, princess).
- Halo settings add an extra layer of protection by surrounding the center stone with smaller diamonds.
2. Remove Your Diamond Jewelry During High-Risk Activities
This is a no brainer – to prevent accidental damage, take off your rings, bracelets, and diamond-studded accessories when:
- Working with heavy tools or machinery
- Engaging in high-impact sports or physical activities
- Cleaning with harsh chemicals (chlorine can weaken metal prongs)
- Cooking or gardening, where hard surfaces and debris can cause unintended damage.
3. Schedule Regular Inspections
Over time, the prongs or settings holding a diamond in place can loosen, increasing the risk of loss or damage. A professional jeweler should inspect and clean your diamond jewelry at least once a year to ensure settings remain secure.
4. Store Diamonds Properly
When not wearing your diamond jewelry:
- Store each piece in a separate compartment or soft pouch to prevent scratches.
- Avoid placing diamonds together, as they can scratch each other due to their hardness.
- Use a lined jewelry box to protect against accidental knocks or pressure.
5. Consider Diamond Insurance
Since diamonds are valuable investments, insuring your jewelry can provide peace of mind in case of loss, damage, or theft. Many insurers offer specialized policies for high-value pieces.
Final Thoughts
Diamonds are extraordinarily hard but not unbreakable. Understanding the difference between hardness and toughness helps diamond owners take the right precautions to prevent chips, cracks, or breakage.
With proper care, high-quality settings, and mindful wearing habits, your diamond jewelry can remain flawless and brilliant for a lifetime.
At Kosmima Fine Jewelry, we offer expert guidance on selecting the perfect diamond for your next piece. Whether you’re looking to browse our collection of diamond pieces, or are looking to create something custom, we can help.
Visit our Chestnut Hill showroom or contact us for a personalized consultation, and let us show you why we’ve been Boston’s preferred diamond jewelers for over the past three decades.
