The world of gemstones can often be confusing, especially when two stones have similar names but vastly different properties. This is the case with zircon stone and cubic zirconia. Despite their similar-sounding names, these two gemstones are distinct in origin, composition, and characteristics. Zircon, a natural gemstone with a history spanning billions of years, is often mistaken for cubic zirconia, a synthetic diamond simulant.
Understanding the distinct differences between zircon and cubic zirconia is crucial for anyone interested in gemstones, whether for personal adornments such as bracelets and earrings, or for investment purposes. While both stones are used to simulate diamonds, their origins, properties, and uses differ significantly. This detailed comparison will help you appreciate the unique qualities of each gemstone and guide you in making informed decisions about its use and value in the world of jewelry.
1. Origin & Composition
Zircon
- Origin: Zircon stone is one of the oldest known naturally occurring gemstones, predating even diamonds. Ancient crystals, such as those found in Jack Hills, Australia, date back approximately 4.375 billion years, making them among the oldest materials on Earth. These crystals have survived geological processes and offer valuable insights into the planet's early history. Other major sources include Sri Lanka, Thailand, Cambodia, Myanmar, and parts of Africa and the United States.
- Composition: Zircon belongs to the group of nesosilicates and is composed primarily of zirconium silicate (ZrSiO4). It often forms a tetragonal crystal structure, showcasing its robust and stable nature. The presence of trace elements can impart various colors to zircon, ranging from colorless to yellow, brown, green, blue, and red.
- Historical & Cultural Significance: Zircon has a rich historical significance, with mentions in ancient texts like the Old Testament, where it adorned the breastplate of Aaron. Its diamond-like luster and fire make colorless zircon a popular diamond simulant and a cherished December birthstone along with tanzanite.
Cubic Zirconia (CZ)
- Origin & Composition: Cubic zirconia (CZ) is a synthetic gemstone composed of zirconium oxide (ZrO2). Scientists have long sought to create a diamond substitute, it was first synthesized in the laboratory in the 1930s and gained popularity as a diamond simulant due to its close visual resemblance to diamond. CZ is created through a process called the Verneuil method, where zirconium oxide powder is heated to high temperatures and then cooled to form crystals.
- Composition: Unlike its natural counterpart, CZ is entirely synthetic and does not occur naturally. Its chemical composition gives it excellent clarity mimicking the optical properties of diamonds. CZ crystals are typically flawless and have a high refractive index, which contributes to their sparkle and fire. Available in various colors by adding different elements, CZ can mimic gemstones such as synthetic sapphire, ruby, amethyst, garnet and more making it a versatile and attractive option for various jewelry applications such as rings and bracelets.
- Popularity & Use: Since its commercialization in the 1970s after improvements in synthesis techniques, CZ has become widely used in jewelry due to its affordability and visual appeal. It is often set in sterling silver, gold-plated settings, or platinum to resemble more expensive gemstones.
2. Durability
Zircon
With a Mohs hardness rating of 6.50 - 7.50, this stone is durable enough for everyday wear but requires care to prevent scratches or damage. This places it in a similar hardness range as gemstones like garnet, making it suitable for various jewellery applications.
Cubic Zirconia (CZ)
CZ is relatively hard, with a Mohs hardness rating of approximately 8.00 - 8.50, making it durable and suitable for everyday wear, similar to natural gemstones like topaz, aquamarine or spinel. This hardness ensures that CZ can withstand minor wear and tear without scratching easily.
CZ is harder than Zircon
3. Clarity
Another important aspect to consider is their clarity. It plays a crucial role in determining the appeal and suitability of these gemstones for various types of jewelry.
Zircon
Zircon is typically transparent and often free of major impurities, offering a natural and realistic appearance. Unlike CZ, natural zircon can include inclusions, which can sometimes enhance its character and uniqueness rather than detract from its value. Its high refractive index and strong dispersion give it an appearance that can rival diamonds, particularly in its colorless form.
Cubic Zirconia (CZ)
CZ, being a lab-created gemstone, is known for its flawless clarity. It is virtually free of imperfections, giving it a perfect, high-shine finish. The controlled environment of its creation process ensures a consistently clear and brilliant product, making it an attractive option for those seeking an affordable yet sparkling stone.
4. Color & Lighting
When comparing these two stones, one of the most striking differences lies in their color and how they interact with light.
Zircon
The purest form of zircon is colorless, and historically used as a diamond substitute due to its brilliance and fire. It can also exhibit a range of colors, including pink, blue, yellow, green, brown, and red. Among these, blue zircon is particularly prized and achieved through heat treatment. Green color zircon is the rarest and often the most valuable due to its scarcity. These natural hues are influenced by trace elements like uranium and thorium, which can impart slight radioactivity in untreated stones.
The stone also has a high refractive index and strong dispersion, which means it can exhibit strong doubling or double faceting, and a high level of sparkle and rainbow-like flashes of color when light passes through it. Its adamantine luster adds to its appeal, making it highly reflective and giving it an appearance of more facets, enhancing its overall appearance.
Cubic Zirconia (CZ)
CZ is primarily produced to be colorless, serving as an affordable alternative to diamonds due to its clarity and lack of imperfections. It can also be manufactured in virtually any color by adding different trace elements during the production process, including synthetic versions of other gemstones like ruby red, sapphire blue, emerald green, and more. Being lab-created, CZ maintains consistent color and clarity, devoid of the natural variations typically found in mined gemstones.
While CZ also has a high refractive index and dispersion, its brilliance and fire are generally less intense. This makes CZ slightly less reflective and can give it a more “glassy” appearance.
CZ can be synthesised in virtually every color to imitate other gems
5. Pricing Factors
Zircon
Zircon's value is influenced by its rarity, especially in fine-gem-quality and larger sizes. While not as rare as some gemstones like spinel, peridot and sapphires, certain colors like pure blue and large, high-clarity stones from specific regions can fetch higher prices due to their scarcity. Intense and vivid hues, coupled with high clarity, enhance its value. Transparent, eye-clean stones command premium prices for their aesthetic appeal.
Larger stones, particularly those over 10 carats and free of significant imperfections, are rare and therefore more valuable. Prices for gem-quality stones may range from $50 to $500 per carat for standard sizes, with exceptional pieces exceeding $1,500 per carat.
Cubic Zirconia
CZ is synthetically produced and is widely available, making it significantly more affordable compared to natural gemstones like peridot, aquamarine and sapphires. Due to its synthetic nature and abundant supply, CZ is priced much lower than natural gemstones. Prices vary based on size and quality but generally range from a few dollars per carat for smaller stones to around $10 to $50 per carat for larger, high-quality CZ.
A CZ Ring serves as an affordable alternative to a diamond ring
Understanding these pricing and value factors helps distinguish between the stones, guiding consumers in their choice based on budget, aesthetic preferences, and desired investment value.
6. How to Tell Zircon Apart From Cubic Zirconia (CZ)
These properties collectively help gemologists and jewelers distinguish between the 2 stones, ensuring accurate identification of these gemstones in jewelry and gemological studies.
- Radioactivity: Natural zircon can exhibit faint radioactivity, which is a characteristic not found in CZ. This property can be detected using specialized equipment to measure radioactivity levels.
- Birefringence: Zircon is a doubly refractive gemstone, meaning it splits light into two rays that travel at different speeds within the crystal, resulting in facet doubling and outlines when viewed through a gemological lens. Cubic zirconia, being cubic in crystal structure, does not exhibit birefringence and shows single refraction.
- Density: CZ is denser than natural zircon. This difference in density can sometimes be detected through precise measurement techniques, although it may not always be easily discernible without specialized equipment.
In conclusion, while both these gemstones share a name and purpose as diamond substitutes, their origins, compositions, and qualities set them apart distinctly. Zircon, a natural birthstone with a geological legacy, offers unique colors and historical allure, while CZ, synthetic and flawless, provides affordability and consistency. Understanding these differences helps in choosing the right gemstone for both aesthetic appeal and investment value in jewelry.
