BrilliantC® — The Ultimate Ideal Cut. Only the top 0.1% of the world’s natural diamonds make the cut.
By DeGem · Last Updated: September 2026 · 5 min read
An ideal cut diamond is crafted with precise proportions, symmetry and polish to support exceptional brilliance, fire and scintillation. For applicable standard round brilliant diamonds, GIA Excellent is the highest GIA cut grade. BrilliantC® builds on this trusted foundation with DeGem’s proprietary focus on cut precision, craftsmanship and assessed light performance.
When choosing a diamond for an engagement ring or another piece of fine jewellery, many buyers begin with GIA. GIA-graded diamonds — often referred to by shoppers as GIA-certified diamonds — come with independent grading information that helps buyers understand quality through the 4Cs: Cut, Colour, Clarity and Carat. At DeGem, clients can also use the Build Your Own Ring service to select a GIA diamond and pair it with a preferred setting to create a personalised ring.
Why Diamond Cut Matters to Brilliance
Among the 4Cs, cut is the characteristic most directly shaped by human craftsmanship. The proportions and angles chosen by the cutter, together with symmetry and polish, influence how light enters a diamond, reflects through its facets and returns to the eye.
This interaction creates three of the visual qualities most closely associated with diamond beauty. Brilliance refers to the return of white light. Fire is the dispersion of light into flashes of spectral colour. Scintillation is the changing pattern of bright and dark areas that appears as the diamond, viewer or light source moves. GIA considers these visual qualities when grading the cut of applicable standard round brilliant diamonds.
Because cut influences all three, two diamonds with similar colour, clarity and carat weight can still present themselves differently. Precise proportions and craftsmanship can create a bright, balanced and lively face-up appearance, while less favourable proportions may allow more light to escape.
What Is an Ideal Cut Diamond?
An ideal cut diamond is commonly understood as a diamond crafted to particularly precise proportions, symmetry and polish with the aim of achieving exceptional visual performance. The term describes a pursuit of cutting precision rather than a separate grade on GIA’s cut scale.
For applicable standard round brilliant diamonds, Excellent remains the highest GIA cut grade. Within that category, different combinations of proportions and facet relationships can still produce different visual results. This is why shoppers interested in exceptional cut quality may also consider the craftsmanship behind the stone and any additional information available about its light performance.
The goal is not simply to achieve a label. It is to create a diamond whose proportions, finish and facet relationships work together to produce a compelling balance of brilliance, fire and scintillation.
Beyond Excellent: The BrilliantC® Pursuit of Light Performance
A GIA Excellent cut diamond is already a trusted choice. BrilliantC® is not positioned as a replacement for GIA, nor is “Beyond Excellent” a separate GIA grade. Instead, it offers clients who want to explore further an additional focus on cut precision, craftsmanship and light performance.
Each BrilliantC® diamond is cut according to DeGem’s exclusive mathematical formula of proportions and angles, currently described by DeGem as patent pending, to optimise light return and minimise light leakage. This level of precision requires additional craftsmanship, with BrilliantC® taking approximately twice as long to cut as a commercial-grade diamond.
Light performance is assessed using ASET® technology, which creates a colour-coded map showing how the diamond gathers and returns light and provides additional insight into optical symmetry, physical symmetry and optical efficiency. Together, precise proportions, meticulous craftsmanship and ASET® assessment define DeGem’s pursuit of Ultimate Light Performance.
ASET® visual illustrating how a BrilliantC® diamond gathers and returns light.
A Highly Selective Natural Diamond Standard
BrilliantC® is offered exclusively with natural diamonds selected to meet DeGem’s proprietary requirements for cut precision and light performance.
Fewer than 0.1% of the world’s natural diamonds are stated to meet the requirements to become a BrilliantC® diamond. This selectivity reflects the philosophy behind BrilliantC®: bringing together natural origin, meticulous craftsmanship and a deliberate focus on light performance.
Discover the BrilliantC® standard
Explore the craftsmanship, precision and philosophy behind DeGem’s Ultimate Ideal Cut.
Discover BrilliantC®
Three Expressions of BrilliantC®
BrilliantC® can be expressed through different settings, from engagement rings to fine jewellery for other meaningful occasions. Three notable settings are Solitaire, Halo and Three-Stone.
The beauty of an ideal cut diamond is influenced not only by the stone itself, but also by how it is presented. Solitaire, Halo and Three-Stone are among the most recognisable diamond ring settings. While each is popular for engagement rings, these styles can also be chosen for anniversary, milestone or personal fine jewellery.
DeGem’s current BrilliantC® jewellery extends beyond bridal pieces into rings, earrings, pendants, necklaces, bracelets and bangles, allowing the diamond to be expressed in different ways and for different occasions.
SOLITAIRE
One Diamond. Full Focus.
A Solitaire diamond setting features one centre diamond, allowing its shape, proportions and light performance to take focus. Its clean, timeless design makes it a natural choice for an engagement ring or a diamond ring for other meaningful occasions.
HALO
Frame the Brilliance
A Halo diamond setting surrounds the centre diamond with smaller diamonds, adding detail and enhancing the ring’s overall presence. It is suited to those who prefer a more decorative look while keeping the centre diamond as the focal point.
THREE-STONE
Balance in Three
A three-stone diamond setting pairs a centre diamond with two side diamonds, creating a balanced and symmetrical design. The combination gives the ring added presence while allowing each diamond to contribute to the overall light performance.
For those specifically exploring bridal designs, DeGem’s engagement-ring selection provides further inspiration across different diamond settings.
Explore DeGem engagement rings
Experience BrilliantC® at DeGem
Choosing a diamond begins with trusted grading information, but it is also a visual and personal experience. Explore the precision, craftsmanship and light performance of BrilliantC® online or through an in-person private viewing at DeGem boutiques in Kuala Lumpur and Selangor.
A private appointment allows you to compare designs, discuss ideal cut and light performance, and consider how Solitaire, Halo or Three-Stone settings suit the way you want to wear your diamond.
Book a Private Appointment → Explore BrilliantC® Collections →
Frequently Asked Questions
Q: Is BrilliantC® a GIA diamond cut grade?
A: No. BrilliantC® is DeGem’s proprietary ideal cut proposition, while Excellent is the highest GIA cut grade for applicable standard round brilliant diamonds. “Beyond Excellent” expresses DeGem’s additional focus on cut precision, craftsmanship and light performance; it is not a separate GIA grade.
Q: How is BrilliantC® light performance assessed?
A: BrilliantC® diamonds are assessed using ASET® technology, which creates a visual map of how a diamond gathers and returns light. The map can provide information about optical symmetry, physical symmetry and optical efficiency, offering additional insight into the craftsmanship of the cut.
Q: Are BrilliantC® diamonds natural diamonds?
A: Yes. BrilliantC® is offered exclusively with natural diamonds selected to meet DeGem’s proprietary requirements for cut precision and light performance.
Q: Which setting best showcases an ideal cut diamond?
A: There is no single best setting. A solitaire keeps the centre diamond as the main focal point, a halo adds surrounding sparkle and visual presence, while a three-stone setting creates balance and greater overall diamond presence. The right choice depends on the wearer’s style and the purpose of the jewellery.
Q: Can BrilliantC® be worn beyond an engagement ring?
A: Yes. BrilliantC® is not limited to engagement rings. DeGem’s current BrilliantC® collections include rings as well as earrings, pendants, necklaces, bracelets and bangles, allowing ideal cut diamonds to be worn for milestones, celebrations or as personal fine jewellery.
About the Author
DeGem
This article is written and reviewed by DeGem's in-house gemstone and fine jewellery specialists — a team with over four decades of expertise in ethically sourced precious gemstones and fine jewellery design.
Since 1980, DeGem has been Malaysia's premier jeweller, and our specialists are dedicated to helping you make informed, confident jewellery decisions.
Last Updated: Oct 2026 │ DeGem Malaysia │ www.degemdiamond.com
