5 Ways to Distinguish Between Lab-Grown & Natural Diamonds

Spotting the difference: Lab-grown and natural diamonds...

Gemology and jewelry have surged ahead: micron-precise lasers, refined finishing tools, and AI‑assisted CAD now produce highly intricate settings. The most transformative shift is the rise of lab-grown diamonds.

Chemically, physically and optically, lab-grown diamonds are real diamonds—generally indistinguishable from natural ones to the naked eye.

This article explains how lab-grown diamonds are made and the reliable ways to tell them from natural stones, from grading reports and laser inscriptions to the specialized instruments used by retailers and gemological labs.✅

An Overview of Lab-Grown Diamonds

So what exactly is a lab-created diamond?

As mentioned, lab-grown diamonds are identical to natural ones chemically, physically and optically. However, instead of relying on the painstaking mining efforts used to retrieve natural diamonds, experts craft lab-created stones in a lab via a few different processes.

The two main manufacturing processes used to create lab-grown diamonds are High Pressure, High Temperature (HPHT) and Chemical Vapor Deposition (CVD).

• For HPHT, scientists replicate the natural process of diamond formation in a lab. They utilize temperatures of 1300-1600℃ and pressures of 5-6 GPa to form diamonds from carbon, which is similar to the high heat, high pressure environment that produces natural diamonds. However, instead of millions of years, the process takes mere weeks!
• CVD is a newer manufacturing process that requires slightly lower temperatures—roughly 700-1300℃—and a special chamber-like structure to produce diamonds. After placing a diamond seed in the chamber, scientists then pump carbon-filled gas into the space that ionizes and allows the carbon to deposit onto the seed freely, slowly building into a diamond.

Both processes result in a lab-grown diamond that’s around 40-75% cheaper than natural stones and more environmentally friendly depending on the process used to create it. As time goes on, lab-grown diamonds are becoming popular, and consumers are realizing that a diamond with natural origins isn’t necessarily better than a lab-created stone!😎

How Can You (Consumers) Distinguish Between Lab-Grown and Natural Diamonds?

Experts and shoppers alike cannot distinguish a natural diamond from a lab-created stone with the naked eye. Instead, the best way to figure out whether you’re looking at a lab-grown diamond is to closely inspect the gem’s official paperwork. This can be done in two different ways:

Method #1: Find the Diamond’s Laser Inscription

Using a diamond loupe or microscope, you or a jeweler can view the diamond’s laser inscription to find out whether it is lab-grown.

Virtually all reputable lab-grown diamonds (excluding very small accent stones) include a statement detailing their lab-grown status and stone identity within the inscription on their girdle.

It typically includes a clear designation—“LABORATORY-GROWN”, “LABGROWN” or “LG”—and a unique report number issued by the gemological lab, which you can enter into its database to retrieve the stone’s official diamond report.

Method #2: Check the Diamond Report

If you already have a diamond report handy, you can utilize it to learn more about whether the particular stone is lab-grown or not, as well as the specs of it.

Diamond reports include important details regarding dimensions, proportions, the 4Cs, fluorescence, and more; most versions even contain a diamond plot that maps out inclusions and blemishes.

Two famous diamond graders, the Gemological Institute of America (GIA) and the International Gemological Institute (IGI), pride themselves on providing extensive diamond reports and rigorous examinations of each diamond that enters their labs.

When it comes to the GIA, their lab-grown diamond reports provide the standard information mentioned above for loose, lab-created diamonds over 0.15 carats. They use the same scale to grade the color and clarity of lab-grown stones as they use for natural gems, but the grade does not denote any “rarity” as it would for a natural diamond.

The IGI is similarly thorough, providing grades for each characteristic of lab-grown diamonds. Furthermore, to avoid confusion, the IGI ensures that all lab-grown diamond reports are yellow rather than white, further denoting the stone’s lab-created status. Each diamond also includes a “Lab-Grown” or “LG” inscription next to its report number on its girdle.

How Do Gemologists Tell the Difference Between Natural and Lab-Grown Stones?

Gemologists have more tools at their disposal for identifying lab-grown diamonds. While they still cannot see differences between lab-grown and natural stones with the naked eye, they can locate specific markers within the stone that can denote its lab-created nature.🔬

Here are three ways gemologists can distinguish between lab-grown and natural stones:

Method #3: Types of Inclusions

While there are no easily visible differences between lab-grown and natural diamonds, gemologists can sometimes study each stone’s inclusions to make an educated guess regarding its origins.

Using a microscope, gemologists can examine the tiny imperfections within each diamond, some of which only appear in lab-created gems.

Natural diamonds may contain feathering, clouds, pinpoints, crystals, and a host of other inclusions. ⚠️However, metallic inclusions are unique to lab-grown stones, more specifically for HPHT lab diamonds, and the presence of these imperfections can tip off gemologists regarding a stone’s growth morphology.

Method #4: Diamond Typing and Nitrogen Content

A little-known fact for consumers: gemologists classify diamonds into types based on the presence and arrangement of nitrogen atoms.

As the formation of natural diamonds is generally exposed to nitrogen, over 98% of natural diamonds are Type Ia, characterized by clusters of nitrogen atoms. By contrast, most CVD-grown diamonds are Type IIa—chemically pure and containing virtually no nitrogen.

Although Type IIa diamonds occur in nature, they are exceptionally rare (under 2%), so their presence strongly suggests a lab-grown origin. HPHT-grown diamonds can be Type Ia or Type IIa, depending on the process.

Method #5: Strain Patterns, Color Zoning, and Ultraviolet Fluorescence

The final way gemologists can detect lab-grown diamonds is by looking for strain patterns, color zoning, and ultraviolet fluorescence.

In addition to distinguishing between natural and lab-grown stones, these differences can even help identify growth morphology in lab-created diamonds.

Strain Patterns

Both natural and lab-grown diamonds can have strain patterns, but they look rather different when observed with a cross-polarized filter.

Natural diamonds contain a crosshatched or mottled strain pattern as a direct result of intense pressure during the formation process.

For lab-grown diamonds, the CVD variants have “banded”, linear patterns, while the HPHT diamonds have little to no strain pattern at all thanks to the uniform pressure they experience during formation.

Color Zoning

Color zoning refers to the diamond’s color distribution based on the concentration of other elements within the stone. When observing the color zoning of natural and lab-grown diamonds, gemologists will notice:

Ultraviolet Fluorescence

Lastly, lab-created diamonds undergo different fluorescence than natural stones. Natural diamonds experience stronger fluorescence while viewed under long-wave ultraviolet light, but the opposite is true for lab-grown stones. Consequently, lab-grown diamonds fluoresce stronger under short-wave ultraviolet light.

What’s more, lab-grown stones have different patterns of fluorescence based on their growth morphology. HPHT diamonds have a cross-shaped pattern that appears over the pavilion or crown, whereas CVD gems produce a striped pattern instead.

Understanding the FTC's Rules on Advertising Lab-Grown Diamonds

Typically, reputable retailers are very transparent regarding each diamond’s origin, but some sellers aren’t as forthcoming. As a result, the FTC has specific guidelines regarding how companies can advertise their lab-grown stones.

Diamond retailers use the FTC’s “Jewelry Guide” as a handbook for creating marketing materials related to the sale of all types of jewelry. Because lab-grown diamonds are a newer addition to the market, the wording surrounding a lab-grown stone’s origins must be clear to avoid misrepresenting the product.

According to the FTC, all lab-created diamonds should be described as “laboratory-grown”, “laboratory-created”, or “[manufacturer name]-created”, and this phrase should appear before the word “diamond” in the product label, description, etc. Other words or phrases may be used before the word “diamond” if they properly disclose the nature of the gem and the fact that it is not a natural diamond.

Retailers may also refer to lab-grown diamonds as “cultured” so long as the phrase is followed by a clear description of the diamond’s origins or utilizes any of the above phrases. However, these rules only apply to lab-grown stones that are physical, optical, and chemical copies of actual diamonds, and “synthetic” gems have their own rules.

Furthermore, this information must be plainly available in ads, product descriptions, and anywhere a consumer may view the diamond. These “truth-in-advertising” rules also apply to social media, where even sponsored posts on Facebook, Instagram, and Twitter must denote the diamond’s lab-grown nature. In short: it cannot just be hidden in a hashtag!🙂

Finally, if a lab-grown diamond is advertised as “eco-friendly” the company must explicitly state HOW that is true: does the manufacturing process waste less water? Less energy? Advertising must be clear regarding “eco-friendly” status, and the retailer must offer materials that verify their claims.

Lab-Grown Diamonds: An Affordable Alternative to Natural Gems

While no one wants to be unpleasantly surprised by a lab-grown diamond when they thought they were purchasing a natural one, these lab-created stones have plenty of benefits and should be considered as an alternative to regular diamonds.

Lab-grown diamonds are affordable, readily available, and environmentally friendly. If you’re looking for an exact replica of a diamond with a smaller price tag and significantly tinier footprint (in most cases), lab-grown stones are the way to go!

When it comes to buying lab-created diamonds, you should definitely still follow the 4Cs of quality diamonds. We recommend reading our lab-grown diamond guide before making a purchase to give you more insight into lab-created gems.

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