Diamonds and cubic zirconia: two stones that sometimes spark confusion. They may share a dazzling appearance but are worlds apart in origin, composition, and price. Diamonds are renowned for their exceptional brilliance and durability—and rightfully so, since they take millions of years to form deep within the magic movement, pressure and heat of the Earth's core. On the other hand, cubic zirconia is a human-made gemstone. With its affordability and striking shine, cubic zirconia has become a popular alternative to diamonds. Discover the key differences between these two gemstones so you can make an informed decision when purchasing jewelry.
What is cubic zirconia?
An alternative to naturally formed diamonds, cubic zirconia is lab-grown zirconium oxide. Because it closely resembles a "real" diamond, cubic zirconia boasts a hardness and fire that may be difficult for the untrained eye to decipher from natural diamonds. While cubic zirconia can be found naturally in the Earth, it’s extremely rare. It occurs as microscopic grains within minerals like zircon and baddeleyite (basically zirconium dioxide). The popular cubic zirconia used in jewelry is made in a lab and has rivaled natural diamonds since 1976.
Cubic zirconia, sometimes called "CZ" in the jewelry world, was first discovered by German mineralogists von Stackelberg and Chudoba in 1937 while examining zircon gemstones. However, they thought their finding was so insignificant that they never even gave their discovery a new name, simply sticking to its scientific name, cubic zirconia.
Zirconium oxide powder is mixed with "stabilizers" (like calcium or magnesium oxide) and melted at extremely high temperatures to create cubic zirconia. These stabilizers help the zirconia form a crystal structure when cooled. Too much stabilizer can make the stone cloudy or weak. Once the melted mixture cools slowly, it forms a clear crystal. This crystal is then cut and polished to look like a natural diamond. To create colored cubic zirconia, small amounts of other metals are added to the mixture before melting, altering the final stone's color.
What’s the difference between diamond and cubic zirconia?
Composition
Diamonds are pure carbon crystals (usually with trace amounts of other elements) formed under extreme heat and pressure deep within the Earth. They are naturally occurring and millions (if not billions!) of years old. On the other hand, cubic zirconia is a synthetic gemstone created in a lab. While diamonds and cubic zirconia both have a cube-shaped crystal structure, diamonds only contain carbon atoms. In contrast, cubic zirconia contains zirconium and oxygen atoms.
Appearance
Diamonds are renowned for their exceptional brilliance, fire and clarity. They have a distinctive sparkle and often contain tiny inclusions that are natural imperfections. Cubic zirconia can mimic the appearance of a diamond, but its brilliance is usually less intense, and it tends to have a more "glassy" look.
Cost
Diamonds are precious stones in high demand, making them one of the most expensive gemstones on the market. Their price varies based on how they are rated on the 4Cs (cut, color, clarity and carat weight). Cubic zirconia, a lab-created stone, is often more affordable and is often used as a budget-friendly alternative to diamonds. Diamonds take billions of years to make, while cubic zirconia only takes several hours. You know what they say: time is money!
Care and maintenance
Diamonds are incredibly durable and require minimal care. Regular cleaning with warm water and mild soap is sufficient. Cubic zirconia, while still relatively hard, is more susceptible to scratches. Avoid harsh chemicals and ultrasonic cleaners, as they can damage the stone. Plan to clean it regularly with a soft cloth to maintain its shine.
How can you identify the difference between diamond and cubic zirconia?
While cubic zirconia can convincingly imitate a diamond, several ways exist to distinguish between the two. One simple method is to examine the stone's brilliance. Diamonds exhibit a distinctive fiery sparkle due to their ability to disperse light. Cubic zirconia, on the other hand, often has that "glassy" appearance mentioned above, with rainbow-like flashes of light. Additionally, diamonds are incredibly hard and resistant to scratches, while cubic zirconia is softer. If you suspect a stone might be cubic zirconia, carefully examine it for any signs of wear or scratches.
For a more definitive answer, professional testing is recommended. Jewelers have access to specialized equipment, such as diamond testers and microscopes, that can accurately determine a stone's identity. These tools can measure properties like thermal conductivity (a measure of a material's ability to conduct heat) and refractive index (a measure of how much light bends when passing from one medium to another), which vary significantly between diamonds and cubic zirconia. Ultimately, if you need clarification on a stone's authenticity, consulting a qualified gemologist is the best course of action.
The great imitator: Cubic zirconia passing as diamonds
Celebrity smarts: Many diamond owners, including high-profile celebrities, own cubic zirconia replicas of their pricey diamonds, allowing them to wear them out in public without the risk of costly loss, damage, or theft. And, for those looking to mimic celebrity style without the hefty price tag, some jewelers sell spot-on cubic zirconia replicas of famous celebrity diamonds.
Protect your important jewelry pieces
While diamonds are more precious and expensive than cubic zirconia, it may be wise to insure both types of jewelry with a personal jewelry insurance policy. Individuals looking for jewelry insurance often think insuring their jewelry through a homeowners insurance policy is the best option. And while home insurance companies may be experts at insuring homes, you should protect your jewelry with jewelry insurance experts. Check your rate from Jewelers Mutual today by clicking the button below.
