Cubic Zirconia: Hardness, Durability, and Care Guide 101
Cubic zirconia (CZ), widely admired for its close resemblance to natural diamond, is recognized for its impressive hardness and durability. Although CZ was first discovered in nature, nearly all cubic zirconia jewelry available today is lab-created. These man-made stones are typically colorless and flawless, making them one of the most popular diamond alternatives in the jewelry industry.
Unlike diamonds, which form naturally, cubic zirconia is produced by melting zirconium and zirconium oxide with other minerals and heating the blend to nearly 5000⁰F. While most CZ gemstones are crafted to appear clear or white, they can also be customized in a wide variety of colors, adding versatility and appeal to jewelry designs.
Going forward, let’s explore the hardness of cubic zirconia, as well as how to maintain its beauty.
What is the Hardness of Cubic Zirconia?
Cubic zirconia (CZ) is created from a blend of materials such as zirconium oxide, calcium, and magnesium. During the manufacturing process, the gemstone is carefully engineered with equal sides and angles, giving it a symmetrical atomic structure.
The atoms are arranged in a distinctive pattern known as the zincblende structure, where they are densely packed to enhance stability and maintain perfect symmetry. This compact atomic design is what gives cubic zirconia its notable hardness and durability. Thanks to this robust structure, cubic zirconia jewelry is well-suited for daily wear and can retain its beauty over time.
Cubic Zirconia Grading Scale & Mohs Hardness
Cubic zirconia gemstones are evaluated based on a grading scale that ranges from 5A, 4A, 3A, 2A, to AB (1A), with 5A representing the highest quality. In addition, CZ is measured on the Mohs hardness scale, typically ranking between 8 and 8.5. This high level of hardness means cubic zirconia is not only durable but also long-lasting, making it one of the most reliable diamond substitutes in the jewelry world.
| CZ Grade | AB (1A) | AA (2A) | AAA (3A) | AAAA (4A) | AAAAA (5A) |
| Mohs | 8 | 8.2 | 8.3 | 8.4 | 8.5 |
| Description | Cloudy & Soft | Fair Clarity & Strong | Mid-Clarity & Hard | Average Clarity & Hard | Very Clear & Hard |
- AB (1A): Considered the lowest grade of cubic zirconia. These stones are generally soft and cloudy but are sometimes used by jewelry artisans to achieve a subtle sparkle effect in designs.
- 2A: A slightly better grade than AB (1A), with modest clarity and brightness. Though not the most durable, this level of cubic zirconia still offers more shine than the lowest grade.
- 3A: The most commonly used grade in the jewelry industry. 3A cubic zirconia strikes a balance between quality and affordability, making it a popular choice for manufacturers when producing everyday jewelry.
- 4A: Made up of stones that don’t quite meet the highest standard but still showcase good clarity and brilliance. These gemstones are often considered blemished 5A cubic zirconia, offering strong visual appeal with reasonable durability.
- 5A: The finest quality of cubic zirconia available. These stones are exceptionally clear, hard, and durable, closely resembling natural diamonds. 5A cubic zirconia is often regarded as the best diamond alternative in jewelry making.
Is Cubic Zirconia as Hard as Diamond?
When it comes to hardness, no gemstone surpasses the diamond. On the Mohs hardness scale, diamond holds the highest score of 10, while cubic zirconia (CZ) follows closely with a rating of 8–8.5. The difference in hardness and durability is mainly due to their distinct chemical compositions.
Diamonds are formed from tightly bonded carbon atoms arranged in a crystal lattice, giving them unmatched strength. By contrast, cubic zirconia is composed of zirconium dioxide, which still makes it a durable gemstone, though slightly softer than diamond.
Because of this, diamonds are more resistant to scratches and blemishes. However, cubic zirconia jewelry can still maintain its brilliance and sparkle if handled and cared for properly.
Key Differences Between Diamond and Cubic Zirconia
- Beauty & Fire: Diamonds have a higher refractive index, which allows them to reflect more light and display greater brilliance. Cubic zirconia, while having a lower refractive index, still offers noticeable sparkle, making it a popular diamond alternative in jewelry.
- Clarity: Natural diamonds often contain inclusions or imperfections formed during their creation. In contrast, cubic zirconia gemstones are lab-created, resulting in flawless clarity and a consistently bright appearance.
- Weight: A cubic zirconia of the same size as a diamond typically weighs more, as CZ is denser. This means that two gemstones of identical dimensions—one a natural diamond and the other cubic zirconia—will not feel the same in weight.
Does Cubic Zirconia Break Easily?
Among gemstones, cubic zirconia (CZ) stands out for its impressive hardness and durability, comparable only to a few stones such as moissanite jewelry. Its strength comes from its dense crystal structure, which allows it to withstand everyday wear and even extreme conditions.
Although cubic zirconia is not prone to breaking, resistance levels vary by grade. For instance, 5A cubic zirconia ranks around 8.5 on the Mohs hardness scale, making it more durable than lower grades such as 1A cubic zirconia, which ranks closer to 8.
What is 6A Cubic Zirconia?
Traditionally, cubic zirconia is graded on a 5-level scale (from 1A to 5A). However, some custom jewelry manufacturers introduce an additional category known as 6A cubic zirconia. This level signifies stones that have undergone more advanced production techniques—ensuring exceptional clarity, color, and cut. These extra steps cater to customers seeking premium, diamond-like brilliance in their jewelry.
What is 7A Cubic Zirconia?
Similar to the 6A category, 7A cubic zirconia is a proprietary grading term used by certain jewelry manufacturers. This designation highlights stones that have been carefully crafted with superior customization, often involving unique designs and precise cutting standards. The goal is to provide jewelry that not only mimics the brilliance of diamonds but also meets the specific tastes and preferences of discerning customers.
How to Care for Cubic Zirconia Jewelry
Caring for cubic zirconia jewelry is simple, but following the right steps will help preserve its brilliance and sparkle for years. Proper maintenance ensures that your jewelry remains as radiant as the day you bought it.
Here are the recommended steps for cleaning and maintaining cubic zirconia jewelry:
- Use gentle methods – Although cubic zirconia resembles diamond, it is slightly softer. Avoid harsh cleaning techniques designed for diamonds, and instead use mild cleaning agents.
- Choose a soft brush – A baby toothbrush or any extra-soft brush is ideal for safely removing dirt without scratching the stone.
- Prepare a mild solution – Mix a small amount of gentle soap with warm water.
- Clean carefully – Dip the brush into the solution and gently scrub your cubic zirconia jewelry to remove stains and buildup.
- Rinse thoroughly – Wash the jewelry under clean, warm water to remove all soap residue.
- Dry with care – Pat the jewelry dry with a soft, clean cloth or towel. Avoid rubbing too hard, as gentle handling will protect the surface and setting.
With regular, gentle cleaning, your cubic zirconia jewelry will maintain its shine and continue to be a brilliant addition to your collection.
Key Takeaway
Understanding the unique characteristics of cubic zirconia highlights that, although it differs from natural diamonds, it remains a remarkably durable gemstone. Available in various grades, Mohs hardness levels, and diverse appearances, cubic zirconia offers both beauty and versatility.
If you’d like to explore more about the brilliance of cubic zirconia jewelry or customize designs to match your style, feel free to contact us for professional service and tailored solutions.
