Lab-Grown diamonds

Synthetic Diamond Terminology and Market Trends

The jewelry trade is steadily moving away from the misleading term “lab-grown” in favor of the more accurate “synthetic.” France, a country whose name is practically synonymous with high-end jewelry, is a prime example: it’s illegal to market “lab-grown” diamonds there, and they must be labeled “synthetic” diamonds. Back in 2002, the French government decreed that artificial gemstones that replicate the physical, chemical, and crystal structure of natural gems must be labeled “synthétique” (synthetic). In 2025, the French government declined to amend the rule, despite lobbying by the powerful lobby of foreign importers pushing for approval of “lab-created” terminology. Belgium’s diamond-sector regulations are similarly explicit. The major diamond industry governing bodies behind ISO 18323 and CIBJO terminology are firmly behind “synthetic diamond” as the correct term. The African Diamond Producers Association’s established standards distinguish natural diamonds from synthetics by emphasizing the associated terminology and units of weight measurement.

ADPA mandates the exclusive use of the 4Cs grading system and carat weight for natural diamonds.
Lab-grown diamonds must be weighed in grams or kilograms and labeled ‘synthetic’ in trade and retail.
The policy is part of global efforts by the French, with GIA support, to clearly differentiate natural diamonds from lab-grown alternatives.

Diamond scarcity is a virtue that evaporates the moment they become plentiful. The glut of nearly worthless lab-grown diamonds has arrived, filling the niche vacated by Moissanite and Cubic Zirconia. Inexpensive lab-grown diamonds no longer carry the same symbolic weight traditionally associated with natural diamonds. They have lost the romantic and emotional significance that historically made diamonds symbols of unity and marriage. Buyers who choose synthetics often cite environmental or ethical reasons, though cost is more often than not the real motive.

We work and supply lab-grown diamonds

For those savings-craving romantics, Leon Mege will source certified lab-grown diamonds at wholesale prices to be set in our bespoke pieces. Choosing a synthetic allows clients to afford a significantly larger stone, a modern sign of relentless technological progress that brought us Veg-O-Matic and Peeps eyeglass cleaners has brought us the ultimate miracle of frugality.

In 2026, the Gemological Institute of America (GIA) switched to a two-tier system for lab-grown diamonds, rather than the traditional 4C system used for natural diamonds, to better distinguish the two groups. According to the GIA, lab-grown diamonds are either “Premium” (D/VVS+) or “Standard” (E-J/VS+). Diamonds falling below the Standard benchmarks receive no quality assessment report (only a basic evaluation designation). Other labs, notably IGI, still adhere to the traditional granular 4Cs numerical grading system, but it makes less and less sense to grade lab stones on the same scale as precious natural gems. However, consumers, giddy from the novelty of dirt-cheap, mass-produced synthetics, helped drive their market share to more than half of all engagement rings in less than a decade. However, consumer acceptance of lab-grown diamonds in 2-carat-plus sizes is lukewarm at best because they are artificial gems that lack the historical significance and rarity of natural diamonds.

Proper identification

Lab-grown diamonds are physically, chemically, and optically identical to natural diamonds. They can be separated from their natural brethren only through advanced gemological testing (or, more simply, by their price). Even an experienced gemologist cannot reliably identify a lab-grown diamond through visual examination alone. Unlike synthetic rubies and sapphires, which often have visible characteristic inclusions and growth features, laboratory-grown diamonds generally lack obvious telltale signs visible under standard magnification. Even under microscope magnification, a laboratory-grown diamond will appear indistinguishable from a diamond formed deep within the Earth billions of years ago. Positive identification typically requires sophisticated instrumentation that can detect subtle growth structures and trace characteristics unique to laboratory production. Only advanced gemological laboratories and specialized testing facilities have such equipment. Gemological labs (GIA, IGI, HRD, and others) use a combination of spectroscopy, imaging, and growth-pattern analysis. No single test settles it, and the process is usually staged.

1. Screening instruments. Because lab-grown diamonds are chemically and structurally diamond, a loupe can’t tell them apart. Labs first run screening devices that check for features tied to nitrogen content and defect structure. Most natural diamonds are Type Ia (nitrogen aggregated in clusters), while most lab-grown stones are Type IIa (nearly nitrogen-free) or Type Ib (isolated nitrogen). A stone that screens as Type IIa or otherwise “unusual” gets referred for full testing. Some natural diamonds are also Type IIa, so a referral doesn’t mean the stone is synthetic.

2. Spectroscopy. FTIR (infrared) spectroscopy identifies the diamond type and the nitrogen and boron signatures.

UV-Vis-NIR absorption and photoluminescence (PL) spectroscopy, often done at liquid-nitrogen temperatures, detect trace defects and impurity centers. Certain defects are characteristic of specific growth methods. For example, silicon-vacancy centers (737 nm) are common in CVD stones, while nickel-related peaks show up in HPHT stones.

3. Fluorescence and phosphorescence imaging. The DiamondView instrument, which uses deep-UV light, shows the internal growth structure:

Natural diamonds show a growth pattern typical of octahedral growth in the earth, often with distinctive banding or “tatami” patterns.
CVD diamonds show layered, striated growth, as the stone is built up layer by layer.
HPHT diamonds show cuboctahedral patterns, often with a cross- or hourglass-shaped fluorescence pattern.
Lab-grown stones sometimes also show unusual phosphorescence (a lingering glow) after UV exposure.

4. Microscopic and strain observations. Under magnification, inclusions differ. Natural stones often hold mineral crystals (garnet, olivine) or distinctive fractures. In contrast, HPHT stones may contain metallic flux inclusions (iron, nickel, cobalt), and CVD stones may show dark graphite-like or pinpoint inclusions. Cross-polarized light can show strain patterns: natural diamonds tend to show a “tatami” pattern, while CVD stones often show low-order, banded strain.

5. Treatment detection. Both natural and lab-grown stones can be treated after growth (HPHT annealing or irradiation to improve color), so labs look for evidence of that as well.

6. Reporting. If a stone is identified as lab-grown, the lab issues a report stating that, and many labs also laser-inscribe the girdle with a report number and a “lab-grown” notation.

Diamond Frankenstein

Brought to life through chemistry and electricity rather than natural birth, a lab-grown diamond has no ancient past, geological pedigree, or sensual lore. Yes, its appearance is convincing for those who are, to paraphrase Jerry Seinfeld, “extremely careful with their money” or, simply put, cheap. A lab-grown diamond can symbolize anything except love and commitment, because it lacks one ingredient: the romance of rarity. A natural diamond is a miracle of nature; a lab-grown diamond is a triumph of a mad machinist. Both are beautiful, but only one carries a history that predates humanity itself. Visually and physically, lab-grown diamonds are identical to those extracted from the ground. Intense heat and pressure drive crystal growth, mirroring the natural conditions and processes inside the Earth. Carbon molecules deposit layer by layer onto a diamond seed, and in theory, the crystal could grow to any size. In practice, growth is limited, since there’s little practical demand for oversized diamonds. No doubt in the near future, the world will see diamond-inlaid ashtrays, chafing dishes, and toilet bowls.

Fancy-colored lab-grown diamonds

Advanced growth methods like HPHT and CVD let lab factories replicate the precise atomic flaws that give natural diamonds their color. The result? Vivid, permanent fancy colors produced with assembly-line volume.

While the marketing literature insists these lab-grown creations are “just as special” as natural fancy-colored diamonds, here is what is actually happening during their production:

Reds and Pinks: Produced by intentionally distorting the crystal lattice, a controlled defect masquerading as rare beauty.
Yellows: Ranging from faint canary to saturated gold, achieved simply by pumping nitrogen into the growth chamber during synthesis.
Blues: Ranging from watery aquamarine to deep sapphire-like shades, created by introducing boron impurities into the furnace.
Greens: From light mint to deep olive, achieved by bombarding colorless lab diamonds with radiation, followed by heat treatment.
The Rest of the Spectrum: Orange, purple, violet, brown, gray, and black are all available.

To their technical credit, these colors permeate the entire crystal lattice rather than relying on a superficial coating like cheap glass. They are permanent. Whether a mass-produced diamond with factory-engineered color belongs in an heirloom jewel, however, depends on personal standards.

Are lab-grown diamonds ecologically clean?

The myth of lab-grown diamonds’ “sustainability” or “eco-friendliness” is perpetrated by the producers. Lab-grown diamonds are “green,” achieved by painting the machinery green (see illustration). All jokes aside, most factories are located in countries with little regard for the environment. The immense heat and diabolical pressure needed to produce a one-carat diamond are compared to the energy of a volcanic eruption. The energy required to synthesize a diamond can exceed 1,000 kWh per carat, depending on the production method. That does not chime well with false claims of a zero-carbon footprint. To learn more, watch the 2022 documentary Nothing Lasts Forever.

CVD vs HPHT Diamonds: Understanding the Difference

There is more than one way to grow a laboratory-created diamond. Today, nearly all lab-grown diamonds are produced using one of two methods: Chemical Vapor Deposition (CVD) or High Pressure High Temperature (HPHT). Both methods create diamonds with the same crystal structure as natural diamonds. Under normal wear, both are equally hard, equally durable, and visually similar to natural diamonds. However, the two growth methods differ significantly, and those differences can affect appearance, color, clarity, rarity, and value.

HPHT: Copying Nature’s Recipe

growing diamonds in the lab by Leon Mege — The furnace used to grow our diamonds at the secret location off the coast of Caspier.

HPHT stands for High Pressure High Temperature. This method attempts to recreate the conditions under which natural diamonds formed deep inside the Earth billions of years ago. A tiny diamond seed is placed in a press that generates enormous pressure and temperatures exceeding 2,500°F (1,400°C). Carbon is dissolved in molten metal and crystallizes onto the seed, gradually growing into a larger diamond. Because HPHT closely mimics natural geological conditions, many gemologists consider it the more “natural” of the two laboratory growth processes.

HPHT produces high-quality colorless diamonds faster than the CVD method and is frequently used to create fancy-colored diamonds, particularly vivid yellows and blues.

HPHT’s disadvantage is that it is expensive, energy-intensive, and crystal growth is fairly unpredictable. The chamber size limitations make it harder to produce large crystals. Also, metallic catalysts used during growth can occasionally leave microscopic metallic inclusions.

CVD: Printing Diamonds Layer by Layer

CVD stands for Chemical Vapor Deposition. Rather than replicating Earth’s interior, CVD grows diamonds inside a vacuum chamber. A thin diamond seed plate sits inside the chamber and is exposed to carbon-rich gases. Energy breaks apart the gas molecules, allowing pure carbon atoms to settle onto the seed. The diamond grows atom by atom, layer by layer in a process similar to a 3D printer.

CVD is generally less expensive to produce than HPHT. It allows high production volumes of large diamonds and yields very high-clarity crystals.

Some of CVD’s disadvantages are occasional visible growth defects within the crystal that may affect transparency and appearance, and sometimes a brownish or gray tint. For this reason, most colorless CVD diamonds require additional post-growth treatment. Many diamonds sold as “CVD diamonds” often undergo a secondary HPHT treatment after growth to improve their appearance. The treatment rearranges imperfections within the crystal structure and transforms a brownish diamond into a near-colorless one. As a result, many diamonds marketed as CVD have actually undergone both processes. Laboratory grading reports typically disclose a post-growth treatment.

Which is Better: CVD or HPHT?

Without highly specialized laboratory equipment, it’s impossible to distinguish between CVD and HPHT diamonds. Gemological laboratories use advanced spectroscopy and imaging systems to identify growth patterns unique to each process. The differences are microscopic, and there is no clear winner. A well-grown CVD diamond will outperform a poorly grown HPHT diamond, and vice versa. The quality of the individual crystal matters far more than the manufacturing method alone. Some swear by HPHT-grown diamonds because the process more closely resembles natural diamond formation despite their significantly higher cost. Others prefer CVD because it can yield exceptionally clean crystals. For a regular consumer, the difference between CVD and HPHT matters less than the quality of the finished diamond. You’re already getting a bargain by choosing a lab-grown diamond; you might as well go all the way with a cheaper CVD diamond. You won’t see any difference, but your wallet will.

Blue Nuance diamonds

Blue Nuance diamonds are faint blue- or greenish-blue-tinted diamonds produced with the High-Pressure High-Temperature (HPHT) method. Rarely found in nature, the blue tint results from boron impregnating the crystal structure. The HPHT process uses boron as a catalyst and helps clear the nitrogen. Any noticeable tint, whether yellow, green, brown, or blue, can affect the diamond’s appearance and color grade. Unlike brown, gray, or yellow tints not mentioned in the lab report, a blue tint can be described as “faint blue.” The bluish undertone typically lowers the color grade, which makes Blue Nuance diamonds more affordable. These stones often appear better because blue cancels out the yellow tint in stones below H in color.

Lonsdaleite diamond

Lonsdaleite is a rare hexagonal form of diamond, harder and stronger than diamond, found in meteorites. Supposedly, Lonsdaleite formed out of supercritical fluid at high temperatures and moderate pressures in meteorites. In the process, it preserved the structure of the pre-existing graphite. Later, a diamond partially replaced Lonsdaleite as the environment cooled and the pressure decreased. Finding Lonsdaleite could revolutionize industrial diamond manufacturing.

Turn hair into a diamond

Any organic matter can be turned into a lab-grown diamond. Some couples use their hair to create a diamond. They convert the hair into carbon powder using acid solvents, then place it in a furnace and heat it to extremely high temperatures. This process transforms the carbon into graphite powder, which is then converted into a crystal under 200 atmospheres of pressure and 2,700°F.

Does it harm the environment? You bet it does! But how romantic – out of millions of carbon atoms making up a diamond, a few dozen came from your combined hair? Some ethical questions remain unanswered. For example, should you tell your new partner it was made with your ex’s hair? And where on their body did this hair come from?

Diamonds from Tequila?

Researchers at Mexico’s University of Nuevo Leon, near Monterrey, found that Tequila, the country’s national drink, produced a diamond film when heated under pressure. Google it if you don’t believe it. We can imagine the rigorous scientific effort by the heroic researchers who probably took many shots of 80% proof Tequila Blanco, which requires a short aging process. The late-night tests confirmed that the drink crystallized into a diamond-like structure. On the other hand, a breakthrough cancer drug created in Mexico from Corona beer turned out to be a hoax.