Cubic Zirconia Explained
In brief: Cubic zirconia is a lab-created gemstone made from the crystalline form of zirconium dioxide. Valued for its exceptional clarity, durability, and affordability, it is the most popular and visually convincing simulant for a natural diamond. Its flawless appearance and accessible price point make it a staple in fashion and fine jewellery collections.
What is Cubic Zirconia?
Cubic zirconia, often abbreviated as CZ, is a synthetic crystalline substance used as a popular and affordable alternative to diamonds. Unlike a diamond, which is a naturally occurring gemstone made of carbon, cubic zirconia is created in a laboratory from zirconium dioxide (ZrO₂). While the mineral form of zirconium dioxide (zirconia) was discovered in 1892, it was not until the 1970s that Soviet scientists at the Lebedev Physical Institute in Moscow perfected the technique to grow single, large crystals for commercial use. This breakthrough made the mass production of high-quality, inexpensive diamond simulants possible.
It is crucial to distinguish a diamond simulant like cubic zirconia from a synthetic diamond. A synthetic diamond shares the exact same chemical composition and crystal structure as a natural diamond, whereas a simulant merely imitates its appearance. Cubic zirconia achieves this imitation with remarkable success, offering a brilliance and fire that, to the untrained eye, is almost indistinguishable from its natural counterpart. Its creation in a controlled environment means it is typically flawless, lacking the natural inclusions often found in diamonds.
How Cubic Zirconia works
The creation of cubic zirconia is a feat of material science, most commonly achieved through a method known as the "skull crucible" process. The process begins with zirconium oxide powder, which has an extremely high melting point of around 2,750°C. To maintain its cubic crystal structure upon cooling to room temperature, a stabilising agent, typically yttrium oxide or calcium oxide, must be mixed with the powder.
This mixture is heated from within using radio-frequency induction. The outer layer of the powder remains a solid crust, acting as a self-insulating container for the molten core, which gives the crucible its name. The molten material is then allowed to cool very slowly and carefully. As it cools from the bottom up, column-like crystals begin to form. This controlled cooling process results in large, flawless stones that can be cut, faceted, and polished using the same techniques jewellers employ for natural gemstones. By introducing different metal oxides into the mixture, manufacturers can also produce cubic zirconia in a vast spectrum of colours.
Key characteristics
When assessing cubic zirconia jewellery, there are several key characteristics to consider. Physically, it is about 75% denser than a diamond, meaning a CZ stone will feel noticeably heavier than a diamond of the same carat size. In terms of durability, it ranks at 8 to 8.5 on the Mohs scale of hardness. This makes it robust enough for regular wear, but it is more susceptible to scratches and abrasion than harder stones like moissanite or diamond. High-quality cubic zirconia should be completely colourless and free of inclusions. It exhibits more "fire" or rainbow-coloured flashes of light than a diamond, a tell-tale sign for a discerning eye.
Comparison table
| Attribute | Cubic Zirconia | Diamond | Moissanite |
|---|---|---|---|
| Composition | Zirconium Dioxide (ZrO₂) | Carbon (C) | Silicon Carbide (SiC) |
| Price Bracket | Low | Premium | Mid-range |
| Durability (Mohs Scale) | 8 - 8.5 | 10 | 9.25 |
| Optical Properties | High dispersion (fire), lower brilliance | Unmatched brilliance, balanced fire | Exceptional fire and brilliance |
| Best for | Affordable fashion, travel jewellery, trend pieces | Engagement rings, investment pieces, heirloom jewellery | Durable and brilliant diamond alternative for fine jewellery |
Who is Cubic Zirconia best for?
Cubic zirconia is the ideal choice for the style-conscious individual who desires the aesthetic of fine jewellery without the associated high cost. It is perfectly suited for those who love to accessorise and follow trends, allowing them to build a versatile collection of sparkling pieces for every occasion. Its affordability makes it an excellent option for creating large, dramatic statement jewellery where a natural gemstone would be prohibitively expensive. Furthermore, it is a practical choice for travel jewellery, providing peace of mind against loss or theft without compromising on elegance. For buyers on a budget, or those purchasing a first piece of fine jewellery, cubic zirconia set in precious metals like sterling silver or 9ct gold offers a beautiful and accessible entry point.
Care and longevity
Proper care is essential to maintain the sparkle and beauty of your cubic zirconia jewellery. Although durable, it can become cloudy over time as its surface accumulates fine scratches and residue from soaps, lotions, and everyday oils. To clean, simply soak the piece in a bowl of warm water with a few drops of mild washing-up liquid. Use a soft-bristled toothbrush to gently scrub away any dirt, paying close attention to the settings. Rinse thoroughly under clean water and pat dry with a soft, lint-free cloth. Avoid harsh chemicals and ultrasonic cleaners. To prevent scratches, store your cubic zirconia pieces separately from harder gemstones, ideally in a soft pouch or a fabric-lined jewellery box. With regular cleaning, your jewellery will retain its lustre for years.
Common questions
Is Cubic Zirconia hypoallergenic?
The cubic zirconia stone itself is chemically inert and considered hypoallergenic. Any allergic reaction experienced while wearing CZ jewellery is almost always caused by the metal in which the stone is set. Base metals containing nickel are common culprits. To ensure your jewellery is suitable for sensitive skin, we recommend choosing pieces set in high-quality, hypoallergenic metals such as sterling silver, 9ct gold, or platinum. At OD's Jewellers, our cubic zirconia pieces are set in precious metals to ensure comfort and quality.
How do you clean Cubic Zirconia?
Cleaning cubic zirconia is a simple process that can be done at home. The most effective method is to use a solution of warm water and a small amount of mild washing-up liquid. Allow your jewellery to soak for several minutes to loosen any dirt or residue. Afterwards, gently scrub the stone and its setting with a very soft toothbrush. Rinse the piece completely with clean water and dry it carefully with a soft, microfibre cloth to avoid water spots and restore its shine.
Is Cubic Zirconia worth the money?
Cubic zirconia offers excellent value for its price. Its worth is not in its resale or investment potential, but in its ability to provide the luxurious appearance of a flawless diamond at a tiny fraction of the cost. This makes it a fantastic purchase for fashion jewellery, occasion wear, or for trying out a style before committing to a more significant investment. It allows for the enjoyment of beautiful, sparkling designs that are accessible, durable, and beautiful. For its intended purpose, it is absolutely worth the money.
Cubic Zirconia at OD's Jewellers
At OD's Jewellers, we offer a curated collection of cubic zirconia jewellery, expertly set in sterling silver and 9ct gold. Our selection focuses on timeless design and exceptional craftsmanship, providing beautiful, accessible options for gifts, special occasions, or simply to enhance your personal style. Explore our collection online or visit us in-store.
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