Professional Jeweler Archive: Round Gems: The Elements of Quality Cutting

February 2004

For Your Staff: Selling Styles

Round Gems: The Elements of Quality Cutting

Here's what to tell customers

In colored gemstones, cut is performed to maximize color first, then to enhance brilliance and proportion. That’s why round cuts are less common in colored gemstones than they’re in diamonds – rounds are designed to maximize a gem’s brilliance and fire first.

However, round colored gems are sometimes used in four- or six- prong settings, tension mountings (only for very hard stones) and bezel settings. They’re also common in colored gem melee used in pavé settings.

Another benefit to round cuts: they’re less prone to chipping – a plus for softer colored gems that fall below diamond and corundum on the Mohs hardness scale used by gemologists.

Quality Factors for Rounds

Take a round colored gem from your showcase, hold it perpendicular to your line of vision and look down through the table. When you’re familiar with the following quality features, you can share them with customers:

  • What you should notice first is a gem’s color, not its brilliance or fire. You should see a minimum of darkened or black areas and a maximum of color.
  • Look for a return of light. Round cuts are tailored to exploit the reflective and refractive optical features of the gem.
  • Table views should face up as well-proportioned circles that are not skewed or broken.
  • Facet junctions should meet clearly and be crisp and sharp, with few to no abrasions.
  • The pavilion should meet the culet (bottom facet) in the middle of the gem. See this in the sapphire pictured.
  • Look at the gem from the side view. The girdle should not be too fat or too thin. It should look in proper proportion to the rest of the gem and be of a size that allows the jeweler to properly mount it in a setting.
  • Turn the gem over and look at it through the pavilion. Pavilion views should also show well-proportioned facets that meet crisply at the culet. Some culets are faceted, others aren’t. Often the culet is protected by the setting because it’s the most vulnerable part.

– by Robert Weldon, G.G.

The Importance of Cut
Not so long ago, gem cutters were instructed to focus on weight retention more than optimum cutting so sellers could garner a higher price for the finished stone. More recently, a premium has been placed on quality cutting that maximizes a gem’s beauty. In this series, we’ll look at cut quality factors in various colored gem shapes. Photo by Robert Weldon.

Three Views of a Round Stone
The standard round brilliant shape accommodates 57 or 58 facets.
Three views of a round brilliant:

Shows the top facets.
Shows the girdle that goes around the gem.
Shows the bottom facets.

Illustrations by Orasa Weldon.

Copyright © 2004 by Bond Communications