Are lab grown diamonds cubic zirconia?

Lab grown diamonds are not cubic zirconia. A lab grown diamond is a real diamond with the same chemical composition, crystal structure, and physical properties as a natural diamond. Cubic zirconia, on the other hand, is a completely different material made from zirconium dioxide and designed to imitate the appearance of a diamond.

This distinction matters when you are choosing an engagement ring or fine jewelry. At PHD Jewelers, many clients in Haverford and across the Main Line ask this exact question while exploring loose diamonds or engagement rings. 

The short answer we share in-store is simple: lab grown diamonds are real diamonds; cubic zirconia is a diamond simulant.

Understanding the difference helps you make a confident choice when selecting a diamond that will represent an important moment in your life.

Why This Question Comes Up So Often

In our Haverford showroom, this question often arises when clients begin exploring diamond options.

Many people have heard about lab grown diamonds but are unsure how they compare to stones like cubic zirconia.

The confusion usually comes from three assumptions:

• Both are created by humans

• Both can appear visually similar at first glance

• Both are alternatives to natural diamonds

• But in terms of structure, durability, and value, the difference is substantial.

From The Jeweler’s Bench

When we show clients a lab grown diamond and a cubic zirconia side by side, the difference becomes clear. Diamonds reflect light with sharper brilliance, while cubic zirconia often appears softer or more glassy.

What A Lab Grown Diamond Actually Is

A lab grown diamond is created in a laboratory using advanced technology that replicates the natural diamond formation process.

The result is a gemstone that is chemically and physically identical to a natural diamond.

Lab grown diamonds have:

• The same crystal structure as natural diamonds

• The same hardness (10 on the Mohs scale)

• The same brilliance and fire

• The same ability to pass professional diamond testing

When viewed under magnification, trained gemologists may see subtle growth patterns that identify the stone as lab created, but to the eye—and even to most diamond testers—a lab grown diamond behaves exactly like a natural one.

Gem Fact

Both natural and lab grown diamonds are composed of pure carbon atoms arranged in a crystal lattice. This structure is what gives diamonds their famous hardness and brilliance.

What Cubic Zirconia Is

Cubic zirconia (often called CZ) is not a diamond.

It is a synthetic material made from zirconium dioxide and developed to resemble a diamond visually.

While cubic zirconia can appear bright and clear, it has very different properties from a diamond.

For example:

• It is significantly softer than diamond

• It scratches more easily

• It tends to become cloudy over time

• It does not reflect light in the same way

Because of these differences, cubic zirconia is typically used in fashion jewelry rather than fine jewelry designed to last a lifetime.

Key Differences Between Lab Grown Diamonds And Cubic Zirconia

When someone compares these two stones, the confusion usually comes from the fact that both are man-made.

However, the similarities end there.

A lab grown diamond is simply a diamond created by modern technology, while cubic zirconia is an imitation designed to resemble one.

Durability In Everyday Wear

Durability matters if the stone will be worn every day—especially in engagement rings.

Diamonds are the hardest natural material on earth. That hardness makes them ideal for daily wear because they resist scratching and maintain their polish.

Cubic zirconia is softer, which means:

• It can scratch more easily

• It may lose clarity over time

• The edges of the stone can become worn

For jewelry meant to last decades—or generations—diamonds offer a level of durability that simulants cannot match.

Expert Tip

If you are choosing a stone for an engagement ring or a piece you will wear daily, durability should be a major factor in the decision.

How Lab Grown Diamonds Are Used In Fine Jewelry

Lab grown diamonds are increasingly chosen for many types of fine jewelry.

They are commonly used in:

• Engagement rings

• Wedding bands

• Diamond studs

• Tennis bracelets

• Custom-designed pieces

Because they are real diamonds, they can be cut into all the classic shapes you expect—round, oval, emerald, cushion, and more.

Many clients exploring custom jewelry at PHD Jewelers appreciate having the opportunity to compare natural diamonds and lab grown diamonds side by side before making a decision.

Visual Comparison: Diamond Vs Diamond Simulant

Understanding the visual differences can also help when evaluating a stone.

While cubic zirconia can look convincing initially, the difference often becomes more noticeable with time and wear.

The Perspective At PHD Jewelers

When someone visits PHD Jewelers, the goal is never simply to sell a diamond. It is to help you understand the stones you are considering so you can choose with confidence.

Lab grown diamonds have become an important option in modern jewelry design. They provide the beauty and durability of a diamond while offering additional flexibility in design choices.

What matters most is clarity in the decision-making process.

Understanding that lab grown diamonds are real diamonds—and not cubic zirconia—helps remove one of the most common misconceptions people encounter while beginning their search.

Discover Your Perfect Diamond With PHD Jewelers

Whether you are exploring lab grown diamonds, natural diamonds, or designing a custom engagement ring, our team at PHD Jewelers is here to guide you.

We invite you to visit our showroom on Lancaster Avenue in Haverford to compare stones in person and explore the possibilities of fine jewelry crafted to mark life’s most meaningful moments.

Call: (610) 679-9191

Email: Sales@phdjewelers.com

Welcome to PHD Jewelers — where knowledge, craftsmanship, and elegance come together to help you discover your perfect diamond.