Do Lab Grown Diamonds Pass a Diamond Tester?

Lab-grown diamonds are becoming increasingly popular, and one of the most common questions shoppers ask is whether they pass a diamond tester.

The short, factual answer is:

Yes — lab-grown diamonds do pass diamond testers.

In fact, they pass all standard diamond testers, including professional instruments, because lab-grown diamonds are chemically, physically, and optically identical to natural diamonds.

What differs is origin, not composition.

Let us break down exactly what this means, how diamond testers work, and the questions clients most often ask when comparing lab-grown and natural diamonds.

What Does a Diamond Tester Actually Measure?

Most diamond testers evaluate thermal conductivity, sometimes combined with electrical conductivity.

1. Thermal Conductivity Testers

  • Natural diamond: extremely high thermal conductivity

  • Lab-grown diamond: the same

  • Cubic zirconia: low

Result:

Both natural and lab-grown diamonds register as diamond.

2. Dual / Advanced Testers (Thermal + Electrical)

These instruments are often used by professionals.

  • Natural diamond: conducts heat, limited electrical response

  • Lab-grown diamond: conducts heat, may show slight electrical conductivity depending on growth method

Result:

Both still register as diamond. Advanced equipment may flag growth origin, not authenticity.

Does That Mean Lab-Grown Diamonds Are “Fake”?

No.

Lab-grown diamonds are real diamonds.

They share the same:

  • Carbon crystal structure

  • Hardness (10 on the Mohs scale)

  • Brilliance, fire, and scintillation

  • Durability for daily wear

The difference lies in how they are created, not what they are.

 

Can You Tell Lab-Grown Diamonds From Natural Diamonds by Eye?

No.

There is no visual difference between lab-grown and natural diamonds detectable by the naked eye — or even under standard magnification.

Professional identification requires:

  • Specialized laboratory equipment

  • Growth pattern analysis

  • Spectroscopy

In everyday wear, the stones are indistinguishable.

Do Lab-Grown Diamonds Scratch or Wear Differently?

No.

Lab-grown diamonds have the same hardness and durability as natural diamonds.

  • Diamond hardness: 10

  • Lab-grown diamond hardness: 10

They are fully suitable for:

  • Engagement rings

  • Wedding bands

  • Everyday fine jewelry

Do Lab-Grown Diamonds Change Color or Cloud Over Time?

No.

A lab-grown diamond will not yellow, fade, or lose brilliance with time.

If a diamond appears dull or discolored, the cause is typically:

  • Oil or lotion buildup

  • Soap residue

  • Wear on the setting, not the stone

Why Do Lab-Grown Diamonds Look the Same as Natural Diamonds?

Because they are.

Both display the same three components of diamond sparkle:

  • Brilliance – bright white light return

  • Fire – controlled flashes of color

  • Scintillation – the sparkle pattern as the stone moves

Cut quality — not origin — determines how lively a diamond appears.

How Professionals Identify Lab-Grown Diamonds

While testers confirm “diamond,” trained professionals use advanced tools to determine origin, such as:

  • Growth pattern analysis

  • Laser inscriptions

  • Laboratory certification

  • Advanced imaging

This ensures full transparency and accurate documentation.

Should You Choose Lab-Grown or Natural Diamond?

Choose a Natural Diamond If You Value:

  • Geological rarity

  • Traditional heirloom perception

  • Long-established market history

Choose a Lab-Grown Diamond If You Value:

  • Diamond authenticity with modern origin

  • Greater flexibility in size or clarity

  • Identical beauty and durability

Both are real diamonds. The decision comes down to personal priorities, not quality.

Visit Greis Jewelers for Trusted Guidance

Understanding the difference between diamond types empowers you to choose confidently — and that clarity is central to the Greisdorf family’s approach.

At Greis Jewelers, every diamond is selected with care, explained with honesty, and presented with the expertise that has defined our family-owned business for generations.

Greis Jewelers

32940 Middlebelt Rd

Farmington Hills, MI 48334

248-855-1730

Explore our diamond collections, custom design services, and expert guidance by visiting our blog or scheduling an appointment.

Whether natural or lab-grown, the right diamond is the one that aligns with your values — and we are here to help you find it.

 

Back to Blog