A growth remnant is an inclusion found in lab-grown diamonds, left behind by the manufacturing process. It’s the lab-grown equivalent of what gemologists call a “crystal” in a natural diamond. Because lab-grown diamonds aren’t formed in nature, grading labs use different terminology: instead of “crystal,” “cloud,” or “twinning wisp,” you’ll see terms like “growth remnant” and “remnant cloud” on a lab-grown diamond’s clarity report.
Why the Term Exists
In natural diamonds, a tiny mineral trapped inside during formation is called a crystal inclusion. It might be another diamond fragment, a garnet, or some other mineral that got caught as the stone grew deep in the earth. These natural crystals often have recognizable octahedral shapes and can even be colorful depending on what mineral they are.
Lab-grown diamonds aren’t formed in the earth, so calling their inclusions “crystals” or “twinning wisps” would be misleading. Those terms describe things that happen during natural geological growth. The American Gem Society and major grading laboratories use “growth remnant” instead, making it clear the inclusion is a byproduct of a controlled manufacturing process rather than millions of years underground.
What Growth Remnants Look Like
Growth remnants look different depending on how the diamond was made. The two main methods, HPHT (high pressure, high temperature) and CVD (chemical vapor deposition), each leave distinct traces.
In CVD diamonds, growth remnants typically appear as dark, high-contrast spots with a graphitized look. Under magnification, they can also show up as color bands or hazy parallel lines that resemble the internal graining you’d see in a natural stone. One GIA-documented example in a 3.14-carat CVD diamond showed a single dark brown band about 2.2 millimeters long, along with parallel whitish bands visible through the pavilion. These features reflect the layered, start-stop cycling process typical of CVD synthesis.
In HPHT diamonds, growth remnants tend to look metallic. They can appear as small spheres or rod-shaped inclusions, which are actually tiny bits of the metal flux (the solvent mixture used to dissolve carbon during growth) that got trapped inside the diamond as it formed.
Growth Remnants vs. Natural Inclusions
The physical difference comes down to origin, shape, and composition. A natural crystal inclusion often has a geometric, octahedral shape because it formed under the same conditions as the diamond itself. It might even be a completely different mineral. A growth remnant, by contrast, is a leftover from the specific chemistry of the growth chamber: graphite particles in CVD stones, metallic residue in HPHT stones.
Cloud-like formations exist in both natural and lab-grown diamonds, but they form differently. In a natural diamond, clouds are clusters of tiny pinpoints or needles that look hazy under magnification. In a lab-grown diamond, similar-looking haziness is called a “remnant cloud” because it results from the manufacturing process rather than geological forces. Twinning wisps, which are common in natural diamonds that grew as twinned crystals, don’t occur in lab-grown diamonds at all since the controlled growth process doesn’t produce natural twinning.
How Growth Remnants Affect Clarity
Growth remnants are graded the same way any inclusion would be. Their size, number, position, and visibility all factor into the diamond’s clarity grade. A small growth remnant tucked near the edge of a stone will have less impact than a dark, centrally located one. If you’re reading a grading report for a lab-grown diamond and see “growth remnant” listed as a clarity characteristic, it functions exactly like seeing “crystal” on a natural diamond’s report. It’s telling you what kind of inclusion is present and where it sits.
For most buyers, the practical question is whether a growth remnant is visible to the naked eye. In diamonds graded VS2 or higher, growth remnants are generally only visible under 10x magnification. In SI1 or SI2 grades, some may be noticeable without a loupe, especially the dark graphitized type found in CVD stones, which can stand out more than lighter inclusions.
How Labs Detect Them
Standard gemological examination with a loupe or microscope catches most growth remnants. But the more sophisticated identification, confirming whether a diamond is lab-grown in the first place, relies on advanced spectroscopy. Photoluminescence spectroscopy, where a laser illuminates the diamond and the resulting light emissions are recorded, can detect atomic-level defects at concentrations as low as ten atoms per billion carbon atoms. The specific pattern of defects reveals whether the diamond grew naturally or in a lab, and what method was used.
Grading laboratories also use deep-UV fluorescence imaging (a tool called DiamondView) to map growth patterns. Natural diamonds and lab-grown diamonds fluoresce in distinctly different spatial patterns. HPHT synthetics, for example, show a cross-shaped growth structure that doesn’t occur in nature, while CVD diamonds display characteristic layered banding. These tools work alongside traditional microscopy to give a complete picture of what’s inside the stone.
What This Means When You’re Shopping
If you see “growth remnant” on a lab-grown diamond report, it simply confirms you’re looking at a lab-grown stone with a specific type of inclusion. It’s not a red flag or a defect unique to lab diamonds. It’s the honest terminology for the same kind of thing that happens in every diamond, natural or not: small imperfections that get trapped during growth. The key factors are still the same ones that matter for any diamond purchase: where the inclusion sits, how large it is, and whether you can see it without magnification.