How Does Gemstone Cutting Affect Color and Sparkle?

When you think about gemstones, you probably think about color first and then how much the stone sparkles. You might imagine the bright red of a ruby, the deep blue of a sapphire, or the rich green of an emerald. What many people don’t realize is that what you see in these stones has just as much to do with the way the gemstone is cut as it does with the natural color inside the rough stone. A well cut gemstone can completely transform a piece of rough material, taking it from something dull and flat to bright and vibrant.

Gemstone cutting is both a science and an art. A skilled gem cutter (also known as lapidaries) studies each piece of rough to determine the best way to cut the stone to show off its best sparkle, color, and size. The angle of even one facet can change how the stone reflects light, which impacts sparkle and how the color spreads from edge to edge. Let’s take a deeper look at how gemstone cutting affects color and sparkle, so the next time you’re shopping for a loose gemstone or a finished piece of jewelry, you’ll feel more prepared to judge the cut quality for yourself. 

Cut in Gemstones vs. Diamonds

Many people know the Four Cs of diamonds (cut, color, clarity, and carat weight), and understand that the cut has the biggest impact on how much a diamond sparkles. But with colored gemstones, the priorities are slightly shifted. The color is the most important quality, with sparkle coming in a close second. A sapphire or ruby needs to show off its richest color possible, and only once that is achieved, the cutter can adjust the cut to add sparkle and light. 

Different stones and shapes require different cutting strategies. For example, sapphires and rubies are often cut slightly deeper to help their color look stronger, while aquamarine is usually cut shallower so it doesn’t look too dark. Emeralds are commonly cut in step cuts to show off their color and mask their natural inclusions. In the end, the cut of a gemstone determines whether it looks vibrant and lively or dull and flat. Even a piece of rough that naturally has great color can be ruined if it’s poorly cut.  

How Cut Affects Color

Several aspects of a gemstone cut can affect how the color is displayed throughout the stone. Let’s break it down:

1. Depth of Cut - When light enters a gemstone, it interacts with the stone’s natural color before reflecting back to your eye. A gemstone that is cut too shallow may look washed out, while one that is cut too deep can look dark or dull because the light gets trapped. The right depth allows the color to show evenly and allows the stone to reflect light. 

2. Color Change - Some gemstones, such as tanzanite or alexandrite, show different colors when viewed from different angles or in different lighting. A cutter can cut the stone to highlight the most attractive color. For example, tanzanite can show blue or violet, but a cutter will usually cut it to emphasize the violet since it’s more prized and rare.

3. Color Zoning - Many gemstones have uneven color distribution with light or dark patches. A skilled cutter can cut the stone to minimize the zoning so the stone looks more evenly saturated.

4. Color Balance - Cutters often have to decide whether size or color is more important. A large, shallow stone may look impressive, but too light, while a smaller, deeper stone may show stronger color saturation. 

How Cut Affects Sparkle 

While color is the most important attribute of colored gemstones, sparkle still plays a major role. Even stones with a beautiful rich color can look bland if they don’t sparkle. Here’s how cut affects sparkle:

1. Facet Pattern - Round brilliant cuts, with many small facets, create the most sparkle. Step cuts, like the emerald cut, offer more of a mirror-like flash than glittery sparkle. 

2. Symmetry - Even if one facet is slightly different from the others, the light performance of a gemstone can be interrupted. Good symmetry allows light to reflect back evenly instead of leaking out the sides, which can make a gemstone appear dull.

3. Polish - The quality of the polish affects how the facets reflect light. Scratches will reduce the stone’s sparkle.   

Gemstone Cuts and Their Effects

1. Round Brilliant Cut - The most common cut for diamonds and many gemstones like sapphires and aquamarines. With 57 or 58 facets, this cut is made to maximize brilliance while keeping color even.

2. Oval Cut - Makes stones appear larger when viewed from the top. If the oval is too elongated, a dark “bowtie” may form across the middle where light does not return to the eye properly.

3. Emerald Cut - A step cut with long, rectangular facets. It focuses on color and clarity, and doesn’t create much sparkle, but with saturated color it can be very beautiful.  

4. Cushion Cut - Rounded corners and large facets show off color and produce a soft sparkle.  

5. Pear and Marquise Cuts - Both are elongated cuts that make the stones look larger, but can show uneven color or reduced sparkle if the cut is not perfectly proportioned. 

What Should I Look For When Buying a Colored Gemstone?

• Look at the color from above. Does it look rich and even or are there pale areas?
• Tilt the stone under different lighting. Does it keep sparkling or does it go dull in certain areas?
  
• Hold the stone over a paper with text. If you can see clearly through it like a window, it’s cut too shallow.
  
• Check the outline and facets. Do they look even and balanced, or does something seem off?

Final Thoughts

When it comes to colored gemstones, cut is just as important as the stone’s natural qualities. The way a stone is faceted determines how it interacts with light and how the color and sparkle appear to the eye. A well cut gemstone will balance depth, symmetry, and polish to show the best color possible and to reflect light back to the eye as much as possible. An experienced stone cutter will evaluate a piece of rough thoughtfully prior to cutting in order to maximize the size, color, and sparkle of a stone. So the next time you’re shopping for a colored gemstone, ask yourself the above questions to assist you in evaluating the cut quality of the stone.