Value Factors, Design, and Cut Quality of Colored Gemstones (Non-Diamond) - Part 1 - Value Factors of Colored Gemstones

Oct 26, 2026

The article analyzes key value drivers for colored gemstones (non-diamonds) in five parts, focusing in this issue on the first two. It explains how cut quality is tied to manufacturing precision—facets, proportions, symmetry, polish, and how they manage light interactions—while also noting how rough quality and inclusions affect final appearance. It quantifies a value framework where color dominates, then covers color science dimensions, uniformity, and practical market effects. Finally, it introduces country of origin and how origin reports and equipment can validate value-impacting provenance.

LanguageEnglish

CategoryResearch & Report

FormatPDF

Pages12

Reading Time30 min

AccessFree to download

Part 1: Value Factors of Colored Gemstones

Cut Quality and Facet Interaction

Rough Material, Inclusions, and Face-Up Color

Color Science: Hue, Saturation, Tone, Uniformity

Market Preferences and Value Implications

Country of Origin

Gem Market News Feature Value Factors, Design, and Cut Quality of Colored Gemstones ( Non-Diamond) Al Gilbertson, GG (GIA), CG (AGS) In this comprehensive article, the author discusses the value factors of colored gems in five parts. This article looks at the first two parts. Future issues of the Gem Market News will continue the discussion, looking at other factors. Part 1: Value Factors of Colored Gemstones For our purposes, the word “cut” means more than just the shape of a gem ; it also encompasses the elements of“cut quality.” Cut quality refers to how well the gem was manufactured, or how well various facets were placed. Combined with the proportions, symmetry, and polish, a well-cut gem should have a beauty that not only comes from its color and clarity, but from how the facets interact with light. This series should illustrate how to assess the elements of cutting, and how to better understand the impact of cut quality on the value of various gems. Part of that will include under standing the choices a cutter makes and why. While our focus is on forms of faceted gems, we will briefly touch on non-faceted gems. The quality of the rough material limits the gemstone ’s final appearance. Therefore cutters prefer rough that is transparent and without many inclusions. Some gems are rarely eye-clean, so some inclusions become acceptable in those materials. Since color is the highest priority for colored gems, how a cutter manages the light as it enters and exits a gem becomes an exercise in artistry. Ruby rough with a deeply saturated red color and free from even minor inclusions under 10X will produce gems of noteworthy face-up color and appearance, even if the fashioning is poor. But if the faceting washes out the color or muddies its color by mixing dichroic colors, the cutter has failed miserably. Josh Hall (Vice President, Pala International, Inc.) helps us put cut in perspective to a gem ’s value (from Hall ’s personal comments—see Fig. 1-1) . He states that color is about 60% of the gem ’s value, followed by the location it comes from which can influence 15% of the value (this can be much more for certain origins, such as Kashmir sapphire) . After that, cut and size each represent around 10% of the value followed by the shape (outline) of the gem. I ’m going to add clarity and color zoning to the discussion below. Each of these can be quite variable. Before we go through each of the value factors in Figure 1-1, it is important to note that the relative value percentages represent Josh ’s experience, but there are always exceptions. For example, in some local retail markets, size and cut can embody more than 10% of the gem ’s value. Certain size ranges and cut qualities can be perceived as more saleable, so a premium can be added. All of these factors are discussed on a basic level. In reality, many are more complicated for each particular gem material. Color is King! In color science, there are three dimensions to color: hue (red, green, blue, etc.), saturation (intensity or richness of a color), and tone (lightness or darkness) . There is a fourth color factor for gemstones: uniformity of color. Our eyes see color as seven colors of the rainbow: red, orange, yellow, green, blue, indigo, and violet. Each of these colors is made ofrays oflight, each traveling at different speeds with different wavelengths. When all of the above colors combine, we see it as white light. When The GemGuide Value Factors of Colored Gemstones January/February 2016u 1 Fig. 1-2. Illustration by Al Gilbertson, © GIA. Row 1: spodumene, sapphire, scheelite, sphalerite, tourmaline. Row 2: sapphire, sapphire, spinel, euclase, spinel. Photos by Robert Weldon, © GIA. white light enters a colored gem, part of the light can be absorbed. For instance, if a gemstone absorbs all of the colors except blue, only the blue will be visible, and we see the gemstone as blue. The optimal color range (combination of hue, sat

FAQs

How does cut quality affect the value of colored gemstones?

Cut quality determines how facets are placed and how proportions, symmetry, and polish interact with light. A well-cut gem’s beauty comes not only from color and clarity, but from facet-driven light performance.

Why is color treated as the highest priority for colored gems?

Color is described as the most important quality factor for non-diamond colored stones. The article links value to measurable color dimensions—hue, saturation, tone, and uniformity—and shows that pale or uneven colors usually reduce value.

How does country of origin influence gemstone value?

Origin or mining location can strongly change value, sometimes dramatically for certain stones like Kashmir sapphire. Grading labs may provide origin reports, and validated provenance can significantly affect pricing.

Oct 26, 2026

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