JEWELRY EDUCATION
Diamonds vs Cubic Zirconia: Understanding the Differences
Diamonds have been captivating the world for years. In recent times, modern technology has given rise to other stones that try to stimulate diamonds, known as diamond simulants. One of the more popular simulants is Cubic Zirconia.
While cubic zirconia may appear similar to a diamond at first glance, it differs significantly in terms of durability, brilliance, value, and long-term appeal.
As fine jewelers, we believe it’s important to provide clear and factual comparisons so that buyers can make informed decisions.
If you’re considering a diamond or weighing it against cubic zirconia, here’s what you need to know about the key differences.
What Are Diamonds and Cubic Zirconia?
Diamonds are naturally occurring or lab-created gemstones composed of carbon atoms arranged in a crystal structure. This composition gives them exceptional hardness, unmatched brilliance, and lasting value. Formed deep within the Earth over billions of years, natural diamonds have been prized for centuries as symbols of beauty and commitment.
Cubic zirconia, on the other hand, is a synthetic material made from zirconium dioxide; it’s made in laboratories and was first introduced as a diamond simulant in the 1970s. While cubic zirconia is designed to mimic a diamond’s appearance, its optical and physical properties are different.
Brilliance, Fire, and Light Performance
One of the most significant differences between diamonds and cubic zirconia lies in how they interact with light.
Brilliance: This refers to how well a gemstone reflects white light. Diamonds have a higher refractive index (2.42), which means they return more light to the eye, creating a crisper, more intense sparkle.
Cubic zirconia has a lower refractive index (2.15–2.18), which results in a softer, less defined sparkle.
Fire: Fire refers to the dispersion of light into rainbow-colored flashes. Cubic zirconia has higher dispersion than diamonds, often producing an almost artificial-looking rainbow effect that lacks the balance and subtlety of a diamond’s brilliance.
Scintillation: Diamonds exhibit a mix of bright white light and dark patterns, which gives them their iconic “scintillation” or sparkle. Cubic zirconia lacks this contrast, resulting in a glassy, less dynamic appearance.
In natural light, diamonds display a sharp, radiant brilliance, while cubic zirconia may appear overly fiery or even hazy after extended wear.
Durability & Longevity
A gemstone’s hardness and durability play a major role in its long-term beauty and wearability.
Diamonds rank 10 on the Mohs hardness scale. They’re commonly known as the hardest naturally occurring material. This extreme hardness means they resist scratching and retain their pristine look for a lifetime and beyond.
Cubic zirconia ranks 8–8.5 on the Mohs scale, which is significantly softer. While this may seem durable, cubic zirconia is far more prone to scratching, dulling, and abrasions over time.
Because cubic zirconia is less dense and more porous, it can get clouds and lose its polish with daily wear. Within a year or two, it may develop surface scratches and lose its initial sparkle, requiring frequent replacement. Diamonds, by contrast, maintain their brilliance indefinitely.
Value and Cost Over Time
Diamonds retain intrinsic value, whether natural or lab-grown, due to their durability, rarity, demand, and natural wonder; natural diamonds are hard to mine. They are often passed down as heirlooms and remain highly desirable.
Cubic zirconia is inexpensive but at the same time has no lasting value. A brand-new CZ may look appealing at first, but once scratched or dulled, it often needs to be replaced—making it a recurring expense rather than an investment.
While cubic zirconia offers a low upfront cost, diamonds provide lasting beauty and value, making them the preferred choice for engagement rings, fine jewelry, and meaningful gifts.
Should You Choose a Diamond or Cubic Zirconia?
While cubic zirconia can be an affordable short-term option, it does not compare to a diamond’s brilliance, durability, and long-term value. For everyday wear—especially in engagement rings, wedding bands, and heirloom pieces—diamonds remain the superior choice.
If you’re in the market for something that just looks nice though, cubic zirconia could work for your situation. It’s a great option for those who just want something that’s affordable and looks nice. Note though, that it doesn’t look exactly like a diamond.
Final Thoughts
If you’re looking for a gemstone that will maintain its brilliance, withstand daily wear, and hold its value over time, a diamond is the clear winner. Cubic zirconia may offer an initial sparkle, but it falls short in longevity, durability, and prestige.
At Kosmima Fine Jewelry, we specialize in fine diamonds and custom-crafted jewelry, offering both natural and lab-grown diamonds that provide the highest quality and beauty.
If you’re considering a diamond for an engagement ring, custom jewelry piece, or heirloom investment, our expert team is here to guide you through every step.
Visit us in-store at our Chestnut Hill showroom or get in touch with our team by phone or email, to see how we can help you find a piece that will be treasured for a lifetime.
