When shopping for fine jewelry, it's natural to compare moissanites and their lookalikes, such as cubic zirconia (CZ) and diamonds. All of these stones may sparkle, but their origins, structure, and long-term value tell very different stories. Whether you're buying your first diamond ring or researching ethical engagement ring options, understanding the key differences between CZ and diamond is essential.
What is Cubic Zirconia?
Cubic zirconia is a synthetic stone made from zirconium dioxide. It’s designed to imitate the appearance of a diamond but lacks the chemical composition and durability that make diamonds unique. Often used in fashion or costume jewelry, CZ is not considered a precious gemstone.
Is cubic zirconia a diamond?
No, cubic zirconia is not a diamond. CZ is created in a lab to mimic the appearance of a diamond. While it may look similar from a distance, cubic zirconia is softer with its 8–8.5 hardness in the Mohs scale, so it’s more prone to scratches, which can cause it to lose its brilliance over time.
Can cubic zirconia cut glass?
Technically, yes. Cubic zirconia can cut glass because it’s harder than glass, which is only 5–5.5 on the Mohs scale of hardness. Since both CZ and diamonds can cut glass, this is not a definitive way to determine whether a diamond is real or fake.
Does cubic zirconia tarnish or turn green?
According to our gemologists, cubic zirconia stones don’t turn green, but they can appear cloudy over time. This “tarnished” look is usually caused by surface buildup, like dirt, oils, or scratches from daily wear. Fortunately, cleaning CZ is simple: just use a soft toothbrush and soapy water to remove any smudges. If the stone has accumulated too many scratches, it can be easily replaced due to its low cost.
If your skin turns green while wearing cubic zirconia jewelry, the culprit is likely the metal setting, not the stone. Many CZ pieces are set in lower-quality metals, rather than gold or platinum. As the outer coating on these metals wears off, it can oxidize and transfer a green tint onto your skin. Read more about the benefits of choosing recycled gold for your jewelry.
How Diamonds Are Different
Diamonds, whether natural or lab-grown, are made of crystalline carbon and celebrated for their brilliance, hardness, and longevity. They are the hardest known natural substance, making them ideal for daily wear and symbolic of endurance. In terms of optics, diamonds reflect light with sharp, bright flashes, whereas CZ tends to give off a softer shimmer.
Diamonds are also deeply meaningful. They often mark life milestones: proposals, anniversaries, personal achievements. Unlike CZ, diamonds, especially those crafted with care and traceable origin, are usually passed down, due to their inherent symbolism and legacy.
Side-by-Side Comparison: Diamond vs. Cubic Zirconia
Feature |
Diamond |
Cubic Zirconia |
Composition |
Crystalline carbon |
Zirconium dioxide |
Hardness (Mohs scale) |
10 |
8–8.5 |
Brilliance |
Strong white light flashes |
Softer shimmer |
Durability |
Extremely durable |
Prone to scratches and clouding |
Value retention |
Holds long-term value |
Very little resale value |
Symbolism |
Legacy, commitment, rarity |
Imitation, fashion-focused |
Why Ecksand Doesn’t Use Cubic Zirconia
At Ecksand, we create jewelry that’s built to last, not just for today, but for generations. That’s why every ring, necklace, and heirloom piece is crafted using natural or lab-grown diamonds. We never use cubic zirconia or other simulants. Our priority is to offer meaningful, ethical, and enduring fine jewelry that reflects your values as much as your style.
Choosing the Right Stone for You
If you're investing in a piece that marks something meaningful, an engagement, a celebration, or a personal milestone, diamonds offer unmatched longevity, brilliance, and emotional value. Cubic zirconia may be affordable, but it doesn’t carry the same weight, in sentiment or in quality.
For those who want a stone that’s ethically sourced, crafted to last, and beautiful in every sense of the word, diamonds remain the clearest choice.
Discover Ecksand’s diamond engagement rings.