The Difference Between Lab Grown Diamonds and Cubic Zirconia

We’re going to level with you: shopping for diamond alternatives can be overwhelming.

You want the look of a diamond, but without the hefty price tag or ethical concerns. Enter two popular options: lab-grown diamonds and cubic zirconia (CZ).

At first glance, they might seem similar.

Sparkly (ooh). Affordable (aah). Conflict-free (eee!). 

But there’s a world of difference between them when you dig a little deeper.

In this guide, we’ll break down exactly how lab-grown diamonds differ from cubic zirconia, so you can make the smartest choice for your style, budget, and values.

Differences In Composition & Physical Properties 

Lab Grown Diamonds

Lab-grown diamonds are, quite literally, diamonds.

They have the same chemical, physical, and optical properties as mined diamonds.

That means:

Pure carbon composition

Crystalline structure

Extreme hardness: 10 on the Mohs scale

Cubic Zirconia

Cubic zirconia is a different material entirely.

It’s made from zirconium dioxide, not carbon.

While it may resemble a diamond, its properties tell a different story:

Softer: 8–8.5 on the Mohs scale

Prone to scratches and dullness over time

Less resistant to heat and pressure

So while both are man-made, only one is actually a diamond. Facts? Checked. In fact, check out more on lab-grown diamonds here.

Differences In Light Performance & Appearance

When it comes to sparkle, lab diamonds have a natural brilliance.

They reflect light with a crisp, white fire that mimics that of mined diamonds perfectly.

Cubic zirconia, on the other hand, often sparkles with a rainbow-like effect.

This is due to its higher dispersion, or ‘fire’.

Some people love the exaggerated sparkle.

Others find it a little too flashy, especially under bright light.

But the bottom line? Lab diamonds look more authentic, especially in natural lighting.

Can You Tell The Difference Between Lab Grown Diamonds and Cubic Zirconia By Eye?

It’s tough (just like a diamond).

A high-quality CZ set in a nice band can fool most people at a glance. From a distance, the casual observer probably won’t notice.

But a trained eye? Or someone comparing the two side by side?

They’ll spot the difference quickly.

Lab Grown Diamonds:

Pass a standard diamond tester

Maintain sharp facet edges

Reflect light in a more refined way

Cubic Zirconia:

Fails diamond tests

Shows rounded facets with wear

Often displays that rainbow fire that can seem artificial

So while both may shine, lab diamonds pass the authenticity test more convincingly.

Differences In Certification and Grading

Lab diamonds are graded using the 4Cs: cut, color, clarity, and carat.

They’re certified by respected institutions like the GIA (Gemological Institute of America) and IGI (International Gemological Institute).

Worth noting: GIA has recently adjusted how it grades lab diamonds.

Rather than individual letter grades, many are now grouped into categories like ‘premium’ or ‘standard’

Lab-grown diamonds are graded just like mined diamonds, using the 4Cs: color, clarity, cut, and carat weight.

To be considered ‘premium’, a lab diamond must meet the highest standards, specifically:

D color

VVS clarity or higher

Excellent polish and symmetry

For round brilliant diamonds, an Excellent cut grade

Lab-grown diamonds that meet a combination of the above qualities - alongside certain minimum criteria - are typically classified as ‘standard’.

This grading helps you compare options fairly and understand what you’re really getting, especially when working within a budget.

IGI still offers more traditional individual grading, but cubic zirconia doesn’t have a formal grading system.

Some sellers use a rating scale (like A to 5A), with 5A representing the best clarity and cut. But there’s no third-party authority confirming those ratings.

Differences Between Price and Value

Let’s talk dollars.

Cubic zirconia is the budget-friendly champion.

A 1-carat CZ ring can cost as little as $30–$100 depending on the setting.

Lab-grown diamonds are much more affordable than mined diamonds, but still a significant investment.

A 1-carat lab diamond might range from $800 to $3,000, depending on its grade and cut.

But here’s the kicker: CZ has almost zero resale value.

Lab diamonds retain some resale value and can be insured just like a natural diamond,

So if you’re looking for an heirloom or an investment, lab-grown wins.

Differences In Resale Value & Insurance

Insurance providers generally do not cover CZ stones.

They’re seen as costume jewelry with low monetary value.

In contrast, lab-grown diamonds can be insured, appraised, and sold.

You may not get back what you paid, but they do retain some measurable value.

Think of it this way:

CZ: disposable sparkle

Lab Grown Diamond: wearable asset

Differences In Longevity & Maintenance

Lab grown diamonds are built to last.

They resist chipping, scratching, and wear, just like mined diamonds (BUT, if you hit a lab or natural diamond the right way, they can chip or crack... but it's rare). 

You can wear them daily without worry.

Cubic zirconia, however, is more fragile.

Over time, CZ stones can:

Scratch easily

Lose their shine

Become cloudy or rounded at the edges

You’ll find yourself cleaning and replacing them more often.

Maintenance Tips For Lab Grown Diamonds & Cubic Zirconia

Lab Grown Diamond maintenance tips:

Use a soft toothbrush and mild soap

Rinse thoroughly with warm water

Dry with a lint-free cloth

Cubic Zirconia maintenance tips:

Clean more frequently

Avoid lotions and oils that cloud the stone

Use a soft cloth and mild detergent

CZ tends to attract dirt, so upkeep is more demanding.

Below, you can find our full jewelry at-home cleaning guide:

Differences In Ethics & Environment Impact

Lab diamonds are a big step forward in ethical & sustainable jewelry.

They eliminate the need for destructive mining, using less water and energy.

Plus, many are made with renewable energy and traceable supply chains.

Cubic zirconia is also mining-free.

However, CZ doesn’t usually come with traceability or sustainability assurances.

It's mass-produced with less regulation.

So both are better than traditional mining, but lab diamonds carry more transparency and prestige.

Differences In Feeling

This might sound minor, but how a stone feels matters.

Lab Grown Diamonds:

Feel colder to the touch

Are heavier

Have a denser, more solid feel

Cubic Zirconia:

Lighter and warmer

Sometimes feels less substantial

Differences In Customization & Setting Options

Lab diamonds can handle heat and pressure, making them ideal for:

Custom settings

Repairs

Sizing adjustments

They behave just like natural diamonds under a jeweler's tools.

CZ is more delicate.

Under high heat, it can:

Crack

Cloud

Discolor

As a result, high-end jewelers often refuse to work with CZ for custom settings.

Which Is Better For Engagement Rings?

Engagement rings are about symbolism, longevity, and daily wear.

Lab diamonds are the clear winner here.

They offer:

Timeless elegance

Durability

Resale and insurance value

Long-term clarity and sparkle

Cubic zirconia is better suited for:

Temporary or placeholder rings

Fashion pieces

Travel jewelry

So while CZ might make sense for a fun accessory, lab-grown diamonds deliver where it matters most.

What Do They Symbolize?

Gemstones often have hidden meanings.

Lab grown diamonds are no different, they typically symbolize:

Commitment

Strength

Endurance

They’re tied to tradition and sentiment.

Cubic zirconia tends to be seen as:

A diamond alternative

A budget-friendly sparkle

Less meaningful in engagement contexts

That doesn’t mean it’s bad - just different.

Are They Both Safe For Sensitive Skin?

Good news: both CZ and lab diamonds are hypoallergenic.

If you have sensitive skin, the metal setting is usually the culprit, not the stone.

Watch out for nickel alloys in cheaper rings, especially with CZ.

These can cause irritation or discoloration.

Stick to:

Platinum

14K/18K gold (mixed with palladium instead of nickel)

Sterling silver (that is Rhodium plated)

If in doubt, ask before you buy.

Shopping Tips For Lab Grown Diamonds & Cubic Zirconia

If you're on the fence, here are some helpful pointers:

For lab diamonds:

Choose certified stones (GIA or IGI)

Prioritize cut and clarity

Buy from trusted retailers

For cubic zirconia:

Opt for 5A-rated or Russian CZ

Look for high-quality settings

Use for fashion or travel pieces

Pro tip:

On a tight budget? Buy a larger CZ as a placeholder.

You can always replace it with a lab diamond later when your budget allows.

Another smart move? CZ travel jewelry.

If you own large, high-value pieces - like 4-carat diamond studs - consider swapping them for CZ duplicates when traveling.

We recommend Lafonn’s Lassaire collection for high-quality travel-friendly options.

Their CZ pieces are designed to mimic the look and weight of fine jewelry.

CZ You Later, Lab Grown Diamonds Win

If you’re choosing between lab-grown diamonds and cubic zirconia, it really comes down to your priorities.

Want longevity, symbolism, and sparkle that lasts? Go with lab-grown.

Need something stylish on a tight budget or just for fun? CZ is your friend.

Both have their place.

But for major milestones and everyday wear, lab diamonds give you the best of both worlds: beauty, ethics, and durability.

Ready to explore lab-grown options?

Browse our certified collection here.