How To Tell Cubic Zirconia From Diamond

In fine jewelry, the distinction between cubic zirconia and diamonds is subtle and significant. We understand the importance of making informed decisions at Greis Jewelers, a family-owned business renowned for its dedication to quality and customer service. This guide, crafted with the Greisdorf family’s expertise, will help you discern between these stunning stones, ensuring your jewelry choices epitomize elegance and authenticity.

Understanding the Basics

What is a Diamond?

Diamonds, nature's marvels, have captivated hearts for centuries. They are formed under the earth's crust through extreme pressure and heat and are the epitome of strength and brilliance. 

Their unique properties of hardness and refraction set them apart in the world of gemstones.

What is Cubic Zirconia?

Cubic Zirconia (CZ) is a man-made stone known for resembling diamonds. It is created through a complex process of melting zirconium oxide powder at high temperatures. While visually similar, CZ has distinct physical properties compared to diamonds.

Visual Differences

Brilliance and Fire

The interplay of light in a gemstone is its heartbeat. Diamonds exhibit a fiery sparkle and a unique brilliance due to their high refractive index. In contrast, while also brilliant, CZ has a different pattern of light dispersion, often resulting in more colored flashes.

Clarity and Color

Diamonds are formed with natural imperfections, known as inclusions, often invisible to the naked eye. CZ, being lab-created, typically boasts flawless clarity. The color of a diamond can range from colorless to light yellow, while CZ usually remains colorless.

Physical and Chemical Tests

The Weight Test

Despite their visual similarities, diamonds, and CZ differ in density. CZ tends to be heavier than a diamond of the same size, a fact easily discerned by an experienced jeweler.

The Fog Test

A diamond's ability to disperse heat rapidly can be observed through a simple fog test. When you breathe on a diamond, the fog dissipates quickly, unlike with CZ.

Professional Testing Methods

At Greis Jewelers, our experts use specialized tools like loupes and electronic testers to determine a stone's authenticity, offering peace of mind in your selection.

Price and Market Considerations

Price Differences

The value of a diamond is reflected in its price, influenced by its rarity and natural formation. CZ, being more readily available and manufactured, is significantly less expensive.

Practical Tips for Buyers

Purchasing from Reputable Sources

Choosing a trusted jeweler is paramount. At Greis Jewelers, we offer exquisite pieces and the assurance of quality and authenticity.

Certification and Appraisal

Our diamonds come with certification, and we provide appraisal services, reinforcing the value and authenticity of your precious pieces.


Distinguishing between cubic zirconia and diamonds is an art refined by knowledge and expertise. At Greis Jewelers, we invite you to experience the blend of luxury, authenticity, and personal service that has defined our family-owned business for generations.

Discover our unique and exclusive collections at Greis Jewelers, and feel free to contact us or make an appointment for a personalized consultation. Our blog offers insights and guides on fine jewelry, reflecting our dedication to excellence and customer service.