Diamond Education
The 4Cs
Cut, color, clarity, and carat. The four things that decide what a diamond looks like and what it costs, and how to balance them.
What You’re Actually Choosing
Every diamond is graded on four things. Cut decides how it sparkles. Color decides how white it looks. Clarity decides whether you can see the inclusions inside it. Carat is its weight. Below are some definitions for each and where we think the right balance sits for most rings.
The 4Cs in detail
Cut
Cut decides how a diamond handles light. It’s not the same as shape. It’s about how the diamond is shaped and finished, which decides how much of the light that enters the stone bounces back at you.
Ideal
The most sparkle. Cut to the strictest proportions.
Excellent
Bright and lively. A step below Ideal.
Very Good
Plenty of sparkle for a friendlier price.
Good
A balanced choice when budget matters most.
Highlighted: the grade we recommend
A well-cut diamond does three things at once: it bounces white light back at you, splits some of that light into little rainbow flashes, and creates a play of bright and dark spots as the stone moves. A diamond that’s cut poorly does less of all three.
Cut grade and shape are different things. A round, an oval, and a pear can each be cut well or cut poorly. Round diamonds have the most cut surfaces, which is why they tend to sparkle the hardest. Oval, pear, marquise, and heart shapes work in a similar way and also do a good job of hiding tiny flaws.
Emerald and asscher shapes are different. They have long, straight lines instead of the busy faceting that creates a lot of sparkle. They look more architectural and less flashy. If you love that look, just know any color or small marks in the stone will show up more clearly than they would in a round or an oval.
A well-cut diamond from the middle of the color and clarity scales typically looks brighter than a poorly-cut one from the very top of those scales. Of all four Cs, cut is where each dollar shows up the most, so it’s worth prioritizing if the budget allows.
Diyona’s pick
Excellent or Ideal sparkles the most. Very Good and Good are smart budget picks, especially in smaller stones, and still look bright in real life.
Color
Diamond color is graded by how little color the stone has. The scale starts at D (no visible color) and ends at Z (a soft yellow or brown). Grades right next to each other look almost the same. The two ends of the scale do not.
D-F
Colorless
G-J
Near Colorless
K
Faintly Warm
Highlighted: the ranges we recommend for most rings
D, E, and F are colorless. Most people can’t tell a D from a G once the diamond is set in a ring, so the difference between the two is mostly in the price. G through J is called “near colorless” and is where most engagement rings land. A J usually takes a trained eye to spot any warmth at all.
K is the warmest grade we carry. It looks slightly warmer than the near-colorless range, especially in larger stones and in shapes like emerald or asscher that show more of the diamond’s surface.
The metal you set the diamond in matters more than people think. Yellow or rose gold sets a warm tone, so a J or K stone blends right in once the ring is on. The same stone in white gold or platinum can look faintly warm next to the cooler band. Match the metal to the diamond, or pick a diamond that flatters your favorite metal.
Shape matters here too. Round, oval, pear, and cushion shapes break light into so many sparkles that any warmth is hard to notice. Emerald and asscher shapes have larger smooth areas, and that’s where color shows up first.
Diyona’s pick
D-F is colorless and the rarest. G-J looks white once the ring is on. K is our warmest grade and the most budget-friendly; it warms beautifully against yellow or rose gold. Any of the three makes a beautiful center stone; pick what fits your metal and your budget.
Clarity
Diamonds form deep underground over millions of years, and almost all of them carry tiny natural marks from that process. Clarity is the grade that measures how visible those marks are, looked at through a jeweler’s loupe (10x magnification).
FL
Flawless
IF
Internally
Flawless
VVS
VVS1, VVS2
VS
VS1, VS2
SI
SI1, SI2
Highlighted: the flawless and near-flawless tier
Two kinds of marks count toward the grade. The internal ones formed when the diamond grew, and they can look like wisps, clouds, dots, or tiny crystals trapped inside the stone. The surface ones are small nicks or scratches on the outside of the diamond. The internal ones matter more for how the stone looks day to day.
“Eye clean” means you can’t see any marks with the naked eye. VS1 is reliably eye clean. VS2 almost always is, depending on where the mark sits inside the diamond. SI1 sometimes is, especially when the mark is near the edge or in a spot a prong will cover. SI2 usually has something you can spot if you look closely, and it’s the most budget-friendly grade we carry.
Shape matters. Round, oval, and pear shapes hide marks well because all the sparkle distracts the eye. Emerald and asscher shapes are quieter and show marks more clearly, since their long lines don’t hide much. The same SI1 grade can look spotless set as a round and noticeable set as an emerald.
So an SI1 with the mark in the right spot can look eye clean, even when the grade alone wouldn’t suggest it. Filter by clarity on the diamond search page and pick the stone that fits the size and price you want.
Diyona’s pick
FL, IF, and VVS look flawless even through a jeweler’s loupe. VS is reliably eye-clean for less. SI stretches the budget further, especially in shapes like round or oval where sparkle hides small marks.
Carat
Carat is a measure of weight, not size. One carat equals 0.2 grams. Two diamonds at the same carat can look noticeably different on a finger, because how the diamond is shaped and cut decides where the weight sits.
Round brilliants, face-up diameter. Other shapes spread differently.
Cut quality protects how big the stone actually looks. A well-cut 1 carat round looks bigger than a poorly-cut one of the same weight. Sometimes a well-proportioned 0.90 ct can look as large as a less-proportioned 1.00 ct, because more of the weight is up where you see it rather than tucked underneath.
Shape changes the visual size too. Pear, oval, and marquise are stretched out, so they cover more of the finger for the same weight. A 1 carat oval looks about as big as a 1.2 carat round. Cushion sits in between. Round and princess shapes pack the weight in tightly, so they tend to look the smallest for their carat.
Prices jump sharply at the round numbers (1.00, 1.50, 2.00 ct), because that’s where the market sets prices, not where the diamond looks any different. Going just under those marks, like 0.95 or 1.45, can save 10-20% with no real change once the ring is on a finger.
Honestly: pick the size that feels right, then balance everything else to fit your budget. Cut quality has the biggest effect on how a stone looks in person, so a smaller well-cut diamond can look just as striking as a larger one cut a bit less carefully. Whatever combination fits, fits.
Diyona’s pick
Pick the size you want first, then balance the other Cs to fit the budget. Cut quality protects how big the stone actually looks.
How We Handle the 4Cs at Diyona
Every diamond is lab-grown, ethically sourced, and graded to the same standards as a mined stone.
Origin
Lab-Grown, Ethically Made
Every diamond is grown in a lab. No mining, no conflict zones, smaller environmental footprint than a mined stone, same chemical and optical properties.
After the sale
Lifetime Warranty
Manufacturing defects, loose stones, and clasp issues are covered for the life of the ring. Repairs ship free both ways from our New York City studio.
