The Importance of Precision Cutting in Colored Gems

In the world of colored gemstones, beauty should never be sacrificed for size or weight—but unfortunately, that’s still the norm. Most colored gems today are cut with one of two goals in mind: maximizing weight or face-up size or some combination of those two. Ideal optical performance is typically not considered at all.

To the untrained eye, commercial gemstones may look fine—but when examined closely, it’s clear that many have been poorly cut and polished. You’ll often see misaligned facet meets, off-center culets, shallow crowns, overly deep pavilions, and polish work that barely reaches the standard of a 14K pre-polish. If this sounds like gibberish to you, don’t worry. We will walk you through an example of a gem we recently recut so you can see the difference yourself.

Before and After Precision Cutting

On the left, you can see a sapphire from Sri Lanka with beautiful, rich color that is poorly cut.  There is excessive extinction, or dark areas where light does not reflect, windowing where you can essentially see through the gem, and poor symmetry. Despite these issues, this is actually one of the better-quality commercial cuts you will find–we didn’t stack the deck by showing some of the much worse stones we see in the market. While many would be satisfied with this gem, we know we can do, and deserve, better.

When we purchased the stone, we had full intentions of recutting it, recognizing that we would lose 20-30% of the weight in order to enhance its brilliance. The commercial-cut stone started at 2.15 carats and measured 7.6 x 5.1 mm.  The final precision-cut gem is now 1.65 carats and 7.1 x 4.6 mm.

Below we have overlaid the before and after images of this sapphire to show the change in diameter to achieve the ideal proportions for a brilliant cut round gem. You can see the red circle outlining the correct final diameter of the gem.  

Why Does It Matter?

The diamond industry faced a similar reckoning in the past. Today diamonds are cut to a much higher standard than they were 100 years ago, prioritizing ideal proportions and light return over pure carat weight. Now we are witnessing the world slowly come around to realizing colored stones can and should be cut to this high standard, as well. When properly cut colored gems can also show high brilliance, and excellent sparkle without dead black zones from extinction or flat lifeless areas from windowing.

Hopefully, this also helps people understand why a precision cut gem costs more, too. As you can see here, sometimes we sacrifice a higher yield to unlock the full potential of a gem.

We’re biased, of course—but we believe precision cutting is absolutely worth it.