The 4C's
The 4C's Simplified
Cut, color, clarity, and carat — the four things that determine how your diamond looks, performs, and is priced.
Cut
Cut is the single most important factor. It determines how much light your diamond returns to your eye — that flash and sparkle people notice across the room.
A well-cut diamond takes in light through the top, bounces it between its facets, and sends it back out as brilliance (white light), fire (rainbow flashes), and scintillation (the sparkle when it moves). A poorly cut stone lets light leak out the bottom, no matter how large or clear it is.
Cut grades range from Excellent to Poor. At Diamondaire, every stone in our collection is graded Excellent or Very Good. We don't carry anything below that because the difference is visible.
Our recommendation: Always prioritize cut. An Excellent-cut 1.0ct diamond will outperform a Poor-cut 1.5ct diamond every time.
Color
Diamond color is graded on a D-to-Z scale, where D is perfectly colorless and Z has a noticeable yellow or brown tint. Most of the differences between grades are invisible to the naked eye — especially once the stone is set.
D–F are considered colorless. G–J are near-colorless and represent the best value: they face up white in any setting and save significantly compared to D–F.
Below J, warmth becomes noticeable. Some people love it in yellow gold settings. Others prefer the icy look of colorless.
Our recommendation: G or H color. They face up beautifully white, especially in white gold and platinum, and the savings are real.
Clarity
Clarity measures the presence of tiny imperfections — inclusions inside the stone and blemishes on the surface. These are natural byproducts of how the diamond formed, whether in the earth or in a lab.
The scale runs from Flawless (FL) down to Included (I1–I3). What matters in practice is whether inclusions are visible to the naked eye. A stone graded VS2 or SI1 will typically look perfectly clean when you wear it — you'd need a 10x loupe to find anything.
Paying for Flawless or VVS1 buys you a cleaner grading report but not a visibly better diamond on your hand.
Our recommendation: VS1 or VS2 clarity. Eye-clean without overpaying. Put the savings toward a better cut or a larger stone.
Carat
Carat is weight, not size. A 1.00ct diamond weighs 200 milligrams. Two diamonds of the same carat weight can look different sizes depending on their cut and shape — a well-cut stone faces up larger because more of the weight is distributed across the top.
Prices jump at round numbers (1.00ct, 1.50ct, 2.00ct) because of demand. A 0.95ct stone can look nearly identical to a 1.00ct stone on the hand and cost meaningfully less.
Popular carat ranges for engagement rings fall between 1.00ct and 2.00ct. Elongated shapes like oval, marquise, and pear tend to look larger per carat than round.
Our recommendation: Consider just-under weights (0.90, 1.40, 1.90) for better value. Pair that with an Excellent cut and the diamond will look larger than its weight suggests.
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