The factors that determine a diamond’s price come from its proportions, symmetry, brilliance, fire, sparkle, and overall polish. Therefore, the cut is extremely important. The cut affects the beauty and light performance of a diamond. “Diamond proportions” refer to the symmetry of the cutting itself.
Today, we’ll explore diamond proportion ratios and answer the question: Is a diamond that is too deep vs. too shallow good — and which one is truly the best?
A diamond’s proportion ratio determines how well it reflects light. It is measured by width, length, and various angles. When choosing a diamond, you need to consider all of these elements together to determine how beautiful the diamond truly is.
Are shallow diamonds good?
When a diamond is cut too shallow, the light entering from the top has very little space to travel. As a result, the light leaks straight out through the bottom instead of reflecting back to the viewer’s eye.
Even though a shallow diamond may appear larger, the light escapes from the bottom, causing the diamond to lack sparkle and brilliance.
Are deep diamonds good?
If a diamond is cut too deep, the opposite effect occurs. The light entering the top of the diamond has too much space to travel, causing it to refract quickly toward another angle due to the narrowness at the bottom of the stone.
As a result, the diamond appears dull and does not reflect light as brilliantly as it should. In addition, an overly deep diamond may look smaller than another diamond of the same carat weight because its face-up surface is narrower.
So, which diamond proportions are the best?
From everything we've discussed, it's clear that diamonds cut too shallow are not ideal, and diamonds cut too deep are also undesirable. So what proportions are considered “good”?
The answer: a well-proportioned diamond.
When a diamond has proper proportions, light enters the stone and reflects internally in the right balance—it doesn’t leak through the bottom but instead returns upward, creating brilliance, fire, and sparkle.
The world-renowned gemological institute, the GIA, uses grading terms like 3EX, Excellent, or Triple Excellent. These all mean the same thing: the diamond has been evaluated and certified to have excellent proportions, symmetry, and polish. With this certification, you don’t need to spend hours analyzing the stone yourself—the report already tells you everything you need to know.
Therefore, a 3EX diamond delivers excellent light performance, stunning sparkle, and strong brightness. It also holds higher value. But if you’re working with a limited budget, we highly recommend prioritizing cut quality over carat weight.
A diamond with great proportions isn’t just more beautiful—it holds long-term value, has stronger resale potential, and is ideal for collecting or investing.
If you’re still unsure about which type of diamond to choose and need expert guidance, feel free to contact PetchChompoo Jewelry. Our professional team is ready to provide personalized advice and valuable information—far beyond what you’d expect from an ordinary jewelry store.
We are true diamond specialists, dedicated to offering exceptional service and a delightful experience at every level.
If you’d like to purchase beautiful jewelry pieces, we also offer nationwide shipping for online orders, complete with a proper certificate of authenticity for your peace of mind.