Are diamonds prone to chipping? The difference between hardness and toughness, and how to handle them properly
"Diamonds are the hardest material on Earth, so a few knocks are nothing to worry about."
Many people share this belief.
To give you the conclusion upfront, it is a common misconception that "hardness" and "resistance to breaking" are the same thing. While diamonds have high hardness, they are relatively vulnerable to impact.
In this article, we look at the difference between Mohs hardness and toughness from the perspective of jewelry specialists, explaining why diamonds crack or chip, situations to be careful about in daily life, and what steps to take in the unlikely event of damage.
Table of Contents
- Why do diamonds crack or chip despite being hard?
- Understanding the difference between hardness and toughness
- Why diamonds crack or chip: The structure of cleavage planes
- Situations to watch out for in daily life
- What to do if your diamond cracks or chips
- Lab-grown diamonds require the same care
- A perspective for choosing: Shapes that are more resistant to impact
- Frequently Asked Questions
- Summary
Why do diamonds crack or chip despite being hard?
The hardness of diamonds and other gemstones is measured by the "Mohs scale," where the diamond sits at the highest value of 10.
However, this Mohs scale is an indicator of resistance to scratching, not an indicator of how resistant a stone is to cracking when struck.
For resistance to impact, we must consider a different metric known as "toughness."
Understanding the difference between hardness and toughness
What is Mohs hardness? | An indicator of scratch resistance
Mohs hardness is an indicator of how resistant a mineral or gemstone is to being scratched. The Mohs hardness of representative gemstones is as follows.
| Gemstone / Mineral | Mohs Hardness |
|---|---|
| Diamond | 10 |
| Ruby, Sapphire (Corundum), etc. | 9 |
| Cubic Zirconia, Alexandrite, Chrysoberyl, etc. | 8.5 |
| Topaz, Spinel, Aquamarine, etc. | 8 |
| Quartz, Jade, Tourmaline, Amethyst, etc. | 7 |
| Tanzanite, Peridot, etc. | 6.5 |
| Opal, Moonstone, Turquoise, etc. | 6 |
While diamonds have the highest hardness of all gemstones, this is purely an indicator of "how difficult it is to scratch." It is important to also consider "toughness," which we will introduce next.
What is toughness? | An indicator of resistance to impact
Resistance to impact is called "toughness." While not numerically scaled like Mohs hardness, the general order of toughness from strongest to weakest is as follows.
| General order of toughness (resistance to impact) |
|---|
| Ruby, Sapphire, Jade, etc. |
| Diamond |
| Alexandrite |
| Emerald, Aquamarine |
| Tourmaline, Garnet |
| Topaz |
| Opal |
| Turquoise |
Even in terms of toughness, diamonds rank relatively high, but because they have a property of being vulnerable to strong impacts from certain directions, it is important not to assume they are "invincible" just because they are hard, and to be careful not to drop or hit them.
Why diamonds crack or chip: The structure of cleavage planes
The atomic arrangement of a diamond contains areas where the bonds are weaker in specific directions; these are called "cleavage planes." If a strong force is applied in these directions, the stone can crack or chip relatively easily.
This is a structural characteristic of the diamond mineral itself, common to both natural and lab-grown diamonds.
Situations to watch out for in daily life
Diamonds can chip or be damaged relatively easily if you accidentally drop them or strike them against a hard object.
It is best to remove your rings during manual labor, sports, or other situations where heavy impacts might occur.
For specific daily care tips and precautions, please see our detailed guide: "Can lab-grown diamonds be worn daily? Durability, care, and tips for longevity."
What to do if your diamond cracks or chips
Do not keep wearing it forcibly
A chipped or cracked diamond cannot be reinforced in its current state.
If you continue to wear it without realizing, the damage could spread if another impact occurs in the same spot.
We recommend that you stop wearing the item and check its condition first.
Consult regarding repairs
The appropriate course of action depends on the condition of the diamond and the setting.
We recommend consulting the store where you purchased it or their customer service department. We also offer consultations regarding stone resetting and repairs.
As the availability and nature of repairs vary depending on the condition of the product, please contact us for individual details.
Lab-grown diamonds require the same care
Since lab-grown diamonds have the same carbon crystal structure as natural diamonds, they possess the same hardness and toughness properties.
Therefore, all the precautions mentioned here apply to lab-grown diamonds as well.
You can also check the basics of lab-grown diamonds in: "What are lab-grown diamonds? Differences from natural diamonds, pros and cons."
A perspective for choosing: Shapes that are more resistant to impact
The susceptibility to impact is also said to change depending on the shape of the cut.
For example, a shape with rounded corners, such as an emerald cut, is considered less likely to have impact concentrated on a single point compared to cuts with sharp, narrow corners.
If you are currently choosing a diamond, please consider this perspective.
Please also see: "What is an oval-cut diamond? Features, appeal, and how to choose without regrets" and "What is an emerald-cut diamond? Features, appeal, and how to choose without regrets."
However, keep in mind that regardless of the cut, the diamond's inherent vulnerability to impact remains the same, so careful handling is always necessary.
View our lab-grown diamond collection ▶
Frequently Asked Questions
Q. Are diamonds really that easy to break?
A. Despite their high hardness, they have a property of being relatively vulnerable to strong impacts from certain directions. Hitting them hard or dropping them can cause them to chip or crack.
Q. Do lab-grown diamonds break in the same way?
A. Yes. Because they share the same carbon crystal structure as natural diamonds, they have identical properties in terms of hardness and toughness and require the same level of care.
Q. Is it okay to wear them every day?
A. Daily wear is possible, but we recommend taking them off when doing housework, sports, or other activities where strong impacts might occur.
Q. What should I do if my diamond chips?
A. Do not continue to wear the jewelry. Consult the store where you purchased it or their customer service department. Repair options depend on the condition of the damage.
Q. Do some cuts resist chipping better than others?
A. Shapes with corners cut off are considered less likely to have impact concentrated on a single point, but caution regarding strong impacts is required for any cut.
Summary
While diamonds have high hardness, they are relatively vulnerable to impact. Understanding the difference between the two indicators—Mohs hardness and toughness—will deepen your understanding of how to handle them in daily life.
By simply keeping two points in mind—removing jewelry when strong impact is expected and consulting a professional if a chip occurs—you can enjoy your jewelry safely for a long time.
