When shopping for a diamond, most people focus first on carat weight. Size is easy to understand and easy to compare. But in reality, cut quality has a far greater impact on how a diamond looks than carat weight alone. A smaller diamond with an excellent cut will often appear brighter and more impressive than a larger stone cut poorly.
Understanding why cut matters more than size helps buyers make smarter, long-term decisions—especially when selecting engagement rings or significant diamond jewelry.
What “Cut” Actually Means
Cut does not refer to shape. Shape describes whether a diamond is round, oval, emerald, pear, or another outline. Cut refers to how well the diamond’s facets are proportioned, angled, and finished.
A well-cut diamond is engineered to:
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Reflect light internally
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Return light through the top of the stone
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Maximize brilliance and fire
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Create balanced sparkle
A poorly cut diamond allows light to escape through the bottom or sides, making it look dull—even if it has high carat weight.
Why Cut Impacts Brilliance
Brilliance is the white light reflected from a diamond. Fire is the colored flashes seen under certain lighting. Scintillation is the sparkle when the stone moves. All three are determined primarily by cut quality.
If proportions are too shallow, light leaks out the bottom.
If proportions are too deep, light escapes from the sides.
If symmetry is off, the sparkle becomes uneven.
A diamond with ideal proportions will appear:
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Brighter
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Larger than its carat weight suggests
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More vibrant in natural and artificial light
This is why cut often creates a stronger visual impact than simply increasing size.
Carat Weight vs Visual Impact
Carat measures weight—not appearance. Two diamonds can have identical carat weight but look dramatically different depending on cut.
For example:
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A poorly cut 1.20-carat diamond may look smaller and less lively
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A well-cut 1.00-carat diamond may appear brighter and more noticeable
Increasing carat weight without considering cut often leads to paying more for size while sacrificing visual performance.
Cut Grades and What to Look For
For round brilliant diamonds, grading labs evaluate cut quality as:
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Excellent
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Very Good
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Good
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Fair
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Poor
When brilliance matters—especially in engagement rings—cut should never fall below Very Good, and ideally should be Excellent.
Fancy shapes (oval, emerald, pear, radiant) are not always given formal cut grades, which makes professional evaluation even more important.
Budget Strategy: Prioritize Cut First
If working within a set budget, prioritizing cut often provides the strongest return visually. Many buyers choose to:
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Slightly reduce carat weight
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Accept minimal clarity inclusions not visible to the eye
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Adjust color slightly
—while keeping cut quality high.
This approach maximizes beauty without unnecessary overspending.
Long-Term Value
Diamonds are worn daily, especially in engagement rings. A diamond that performs well in light maintains its appeal for decades. Cut quality influences:
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Long-term satisfaction
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Resale appeal
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Overall presence
Carat weight is visible on paper. Cut is visible every time the diamond catches light.
Diamond Selection at Johnston Jewelers
At Johnston Jewelers, diamond selection begins with cut quality. Before discussing size, we evaluate light performance, symmetry, and proportions to ensure the stone performs as intended.
With over 53 years of experience, Johnston Jewelers guides clients toward diamonds that balance cut, carat, color, and clarity—without overemphasizing size at the expense of brilliance. A well-cut diamond will always outperform a larger diamond cut without precision.