How to Tell Lab-Grown Diamonds from Natural Diamonds

People, when buying a diamond, always want to make the smartest decision at a glance, as the market is rushing with diamond alternatives. About 84% of buyers have heard of lab grown diamonds. Still, nearly half of them feel unsure about picking them out from natural ones.

This isn’t about to make a difference, which one is “better” than the other; the whole point is about knowing what you’re buying, whether it is a natural one or just an alternative to that.

This post is for you if you are deciding to make an investment by buying diamond jewelry. This shows how you can make a difference between two just by looking at them.

Let’s get right into it and learn what sets them apart.

Quick Table: How to Spot a Lab-Grown Diamond & Natural Diamond at a Glance

What to Look For	Natural Diamond	Lab-Grown Diamond
Inclusions (Imperfections)	Tiny white dots, cloudy spots, or small crystals inside	Black dots, metallic specks, or very clean-looking clarity
Color or Tint	Clear or slightly yellowish overall color	Sometimes shows slight grayish, brownish, or bluish tints
Growth Lines or Patterns	Usually, none is visible to the eye	May have fine lines or a layered look under strong light
Laser Inscription on Edge	Often blank or just a certificate number	Often says “LAB-GROWN,” “LG,” or similar marking
UV Light Reaction (if available)	Usually glows blue under UV light	May glow orange, yellow, or green
Price Compared to Same Size	Generally higher	Often noticeably more affordable

Can You Tell a Lab-Grown Diamond from Natural? Key Differences For a Consumer

Can You Tell a Lab-Grown Diamond from Naturala

istock/ wragg

Usually, there is a clear difference between the lab diamonds and natural ones, but they are mostly differentiated on the basis of the following criteria.

1. Inclusions & Internal Characteristics (Clarity Differences)

Every diamond has internal features called inclusions, which are microscopic imperfections formed during the crystal growth process. These can reveal how the diamond was created:

Natural diamonds formed under geological pressure and high temperatures, and they often contain:

Pinpoints (tiny white dots)
Crystals (inclusions of other minerals)
Feathers (tiny internal cracks)
Twinning wisps (distorted crystal growth lines)

Their inclusions tend to be randomly distributed, often irregular or organic in shape.

Lab-grown diamonds are formed under controlled conditions in a lab using HPHT (High Pressure High Temperature) or CVD (Chemical Vapor Deposition) processes.

HPHT-grown diamonds often contain

Metallic flux inclusions (iron, nickel)
Black specks or internal graining from growth catalyst residues

CVD diamonds may show

Layered or columnar growth structures
Strain lines or striations not seen in nature

👉 Use a 10x jeweler's loupe to inspect clarity. Look for metallic inclusions or consistent patterns, which are indicators of lab synthesis.

2. Grainings, Striations, and Growth Patterns

The growth structure is another reliable differentiator. Diamonds, whether natural or lab-created, reveal their formation history through internal grain lines or growth zoning under magnification.

Natural diamonds crystallize over millions of years deep within the Earth. Exhibit chaotic, irregular growth zoning or distorted graining. Commonly show natural strain patterns and birefringence (visible under polarized light).

Lab-Grown Diamonds

Grow much faster and more uniformly.
HPHT diamonds may have crosshatched or radial graining.
CVD diamonds often show linear or parallel striations and “stacked sheet” growth layers.

These patterns are often visible under a standard microscope (40x60x) or even under a high-powered jeweler’s loupe if the lighting and angles are right.

3. Fluorescence and Phosphorescence Under UV Light

Many diamonds fluoresce under long-wave ultraviolet (UV) light, and this can sometimes be used to distinguish origins.

Natural Diamonds typically show blue fluorescence under UV light. Some may appear inert (no reaction), and others exhibit faint to strong blue. Rarely show persistent phosphorescence (glow after UV is turned off).

Lab-Grown HPHT diamonds can exhibit:

Yellow, orange, or green fluorescence
Strong phosphorescence (especially in Type IIb diamonds)
CVD diamonds may appear dull or mottled under UV due to irregular growth conditions.

🛠️ Tip: You can buy a cheap UV flashlight online and test this in a dark room. While not 100% definitive, unexpected or vivid colors may indicate a lab-grown stone.

4. Girdle Inscriptions and Laser Markings

Modern diamonds, especially those sold online or by reputable jewelers, are laser-inscribed on the girdle with details about their origin and certification.

Use a loupe to inspect the girdle (the edge around the diamond).

Look for words like:

“Lab-Grown”
“LG”
Certification ID numbers (e.g., GIA 12345678)

Ask for a Grading Report - The Most Reliable Way to Verify a Diamond’s Origin

Lab-created diamonds almost always have inscriptions that include:

Type of growth method (CVD or HPHT)
Lab certificate number
“Lab-Created” or “Man-Made”

⚠️ Note: Not all inscriptions are visible without proper lighting or may have been polished off during setting. Always match the diamond to its grading report.

Why Knowing the Difference Matters

Identifying a diamond’s origin isn’t just about pride or preference. It affects:

Cost – Natural diamonds are more expensive.
Ethical Choices – Some prefer lab-grown for environmental or ethical reasons.
Resale & Insurance Value – Natural diamonds often retain more value, and last for a long time if properly maintained.

Also explore How much lab diamond hold resale value.

Knowing the difference helps you make informed choices. Whether it’s an engagement ring, an heirloom, or a loose stone, you deserve clarity and honesty.

Explore Our Certified Diamond Jewelry Collection

The Bottom Line

Being able to tell a lab-grown diamond from a natural one brings peace of mind. Some admire the perfect shine of a lab-created piece. Others lean toward the hidden history in an earth-made stone.

What counts most is the clear truth. Always request papers that show where they came from.

If you feel any doubt, pause and reach out to someone with real knowledge. A diamond is a sign of care and meaning. You should feel confident with each step you take toward this special purchase.

How to Tell a Lab-Grown Diamond from a Natural Diamond