How To Tell Cubic Zirconia From Diamond

Welcome to Paramount Jewelers! As a leading jewelry retailer, we understand the importance of educating our clients on the products we sell. In this blog, we will discuss how to tell cubic zirconia from diamonds, a crucial skill for anyone interested in buying fine jewelry.

Before we dive into the differences between cubic zirconia and diamond, let's briefly define each. Cubic zirconia is a man-made gemstone made from zirconium dioxide, while diamonds are natural gemstones formed from carbon. While cubic zirconia may be less expensive than diamonds, diamonds are generally more valuable and desirable due to their rarity, durability, and brilliance.

Understanding the differences between cubic zirconia and diamond is important when making a jewelry purchase. Here are some key differences to consider:when jewelry shopping.

Composition and Physical Properties:

  • Chemical composition of cubic zirconia: ZrO2
  • Chemical composition of diamond: C
  • Physical properties of cubic zirconia: high dispersion and refractive index, lower hardness
  • Physical properties of diamond: high dispersion and refractive index, higher hardness 

Differences in Appearance:

  • Brilliance and Fire: Diamonds typically have more brilliance and fire than cubic zirconia.
  • Color: Diamonds can have a range of colors, while cubic zirconia is generally colorless.
  • Clarity: Diamonds have varying levels of clarity, while cubic zirconia is generally flawless.
  • Cut: The cut of a diamond is more precise and intricate than cubic zirconia.

Now that we've covered the differences, let's talk about how to tell cubic zirconia from a diamond. There are several methods you can use:

Visual Inspection:

  • Using a Loupe: A loupe is a magnifying glass that allows you to inspect the stone's facets for clarity and other features.
  • Viewing the Stone from Different Angles: Light behaves differently when passing through a cubic zirconia and a diamond, allowing you to distinguish between the two by viewing the stone from different angles.
  • Using a Diamond Tester: A diamond tester uses electrical conductivity to determine whether a stone is a diamond or cubic zirconia.

Other Known Tests:

  • Heat Test: Diamonds disperse heat quickly, while cubic zirconia takes longer to disperse heat.
  • Scratch Test: Diamonds are one of the hardest substances on earth and can scratch most other materials, while cubic zirconia is softer and more easily scratched.
  • Weight Test: Diamonds weigh more than cubic zirconia of the same size.
  • Refractivity Test: Diamonds have a higher refractive index than cubic zirconia, meaning they bend light more.


In conclusion, knowing how to distinguish between cubic zirconia and diamond is an essential skill for anyone interested in buying fine jewelry. At Paramount Jewelers, we take pride in educating our clients and helping them make informed purchases. If you're interested in learning more or scheduling an appointment, please visit our website at or contact us directly.