Round Cut: Complete Guide
The four standard views of this design: facet layout from above, two profile views showing crown and pavilion depth, and the facet pattern seen from below. This design uses a 96-position index gear.
Beginner to intermediate
2 to 4 hours, depending on stone size
Its symmetry makes every alignment error obvious, which makes it the best teacher
The round brilliant is the most widely taught pattern in amateur faceting, and for good reason. Its radial symmetry means that if your tiers are not even or your index is off, you will see it immediately in the finished stone. Master the logic behind this cut and it carries over directly to ovals, princess cuts, and most other designs on this site.
Pictured throughout this guide: a blue topaz cut using this same round brilliant design.
Anatomy of a round brilliant
Tiers and meet points
Facets are cut in rings called tiers, starting near the girdle and working toward the culet on the pavilion, then from the girdle up to the table on the crown. Within each tier, every facet is cut at the same angle so their edges line up exactly where they meet the tier above or below. These junctions are called meet points, and keeping them sharp and consistent is what separates a clean round brilliant from a cloudy one.
Step by step
Use a proven round brilliant pattern in GemCad sized to your rough, rather than guessing angles from scratch.
Mount the stone pavilion-side up and rough out the general shape before cutting any facets.
Cut the first tier of large pavilion facets, using the index gear to keep them evenly spaced.
Cut the second pavilion tier so its facets meet the mains cleanly, then pre-polish and polish the whole pavilion.
Mount a new dop on the finished pavilion and check laser alignment before cutting a single crown facet.
Work the crown mains, star facets, and upper girdle facets in tiers, finishing with the flat table, then polish.
A note on angles
Facet angles are not arbitrary. They are chosen so light entering through the crown reflects internally off the pavilion facets rather than leaking out the back, a property tied to the stone’s refractive index. This means the ideal angles differ slightly between materials such as quartz, topaz, or corundum. Rather than using a single fixed angle set for every stone, match your design to the material you are cutting, most published GemCad designs list the refractive index they were calculated for.
The exact angle table for the design pictured in this guide will be added here once available.
Pitfalls specific to this cut
Because the design is fully symmetric, any inconsistency in facet depth within a tier is immediately visible from directly above.
A girdle that varies in width around the stone is a common sign of an off-center pre-form or transfer.
If the pavilion mains are not cut to identical depth, the culet point drifts off the true center of the stone.
Build on this cut
Ready to try a different shape?
Once a round brilliant feels comfortable, the same principles carry over to ovals and princess cuts.
Explore Other Cuts →