Skip to content

Sell With A Story: 8X™ Lab-Grown Diamonds

8x diamond lab grown

GCAL’s new ultimate diamond cut grade guarantees excellence in all eight factors.

We’re excited to let you know that Stuller has expanded our lab-grown diamond assortment to include GCAL 8X™ lab-grown diamonds. So, what exactly does the 8X represent? It is the ultimate achievement in precision diamond cutting!

GCAL (the Gem Certification & Assurance Lab) developed the 8X cut grade standard to distinguish the best of the best diamonds. Only extraordinarily brilliant and beautiful diamonds achieve an excellent grade in all eight aspects of cut quality assessment.

Grading Factors

1. Polish
2. External Symmetry
3. Proportions
4. Optical Brilliance
5. Fire
6. Scintillation
7. Optical Symmetry
8. Hearts & Arrows

The GCAL 8X ultimate cut grade gives our discerning jewelers a way to confidently select the most brilliant and beautiful diamonds when purchasing online. With an 8X lab-grown diamond, its physical precision, light handling ability, and optical excellence are all guaranteed. Shop our new assortment of 8X round lab-grown diamonds here.  

Physical Precision

The first three of the 8X grading factors analyze the exactness of the physical surface, the facet shapes, as well as the angles.


Skill and time are required to produce a well-polished lab-grown diamond. GCAL gemologists examine every facet to ensure it is free of polish marks, burns and scratches.

External Symmetry

Master cutters identically shape each facet around the diamond and ensure they are perfectly aligned. Only diamonds with precision faceting achieve a GCAL excellent grade.


Optical scanning technology measures each facet and angle to produce an accurate, to-scale diagram of every diamond.

Light Handling Ability

The next three of the 8X grading factors analyze the light-handling ability of a diamond. The combination of these factors is the essence of what makes any lab-grown diamond visibly shine, dance, and sparkle from across a room.

Optical Brilliance

Optical Brilliance is the overall return of white light to the viewer. It is measured to the thousandth decimal place. White areas indicate light return/brilliance, while dark blue areas indicate light loss.


Fire results when white light travels through a diamond and is dispersed into its rainbow of spectral colors. These flashes of color contribute to sparkle and are best viewed as the diamond moves. Each 8X lab-grown diamond certificate has a video demonstrating its fire.


Scintillation refers to the flashes of white light, or sparkle, produced when light is reflected from a diamond as it moves. Each 8X lab-grown diamond certificate has a scintillation video demonstrating the light returned from a single beam of light when the stone is rotated.

Optical Precision

The last two 8X grading factors scrutinize the craftsmanship and the precise alignment of the crown and pavilion facets in harmony, to achieve aesthetic perfection.

Optical Symmetry

Optical Symmetry is visualized in a photograph of the lab-grown diamond taken in a specific-colored lighting environment. The evenness of the pattern illustrates the precision and uniformity of facet shapes and alignment.

Hearts & Arrows

Precision faceting is visualized as Hearts & Arrows when diamonds are viewed in specific lighting conditions. Each pattern is the result of superior facet placement and exact alignment.

Interactive 8X Guaranteed Certificates

Each 8X lab-grown diamond comes with an interactive GCAL grading certificate that includes a dazzling 360-degree video, fire video, scintillation video, Gemprint® fingerprint image, photomicrographs, to-scale proportion diagram, and laser inscription.

Visit to learn more about 8X lab-grown diamonds and view an interactive GCAL grading certificate.

When you purchase an 8X lab-grown diamond from Stuller, you’ll receive lifetime trade up at a fair market value for another lab-grown diamond with report.

For more information on lab-grown diamonds, check out our previous blogs:

Lab-Grown Diamonds: What You Need To Know

Lab-Grown Diamonds: Knowing What You’re Getting


Olivia Billet

Product Manager, Diamonds

Olivia attended the University of Louisiana at Lafayette, graduated with a bachelor’s degree in Public Relations, and is certified through GIA as an Applied Jewelry Professional as well as a Certified Sales Associate through the American Gem Society. Years of digging through her mom and grandmothers’ jewelry boxes lead to a love of diamonds and gemstones which she leans on every day in her role at Stuller.