Cut
The only C a person makes. Excellent returns light. Poor leaks it through the bottom. No setting fixes that.
Guides
The 4 Cs.
Cut, color, clarity, carat. Grades on paper. What we care about is how the stone takes light, sits in the head, and holds. Move the sliders.
Live stone
Watch the grade, not the brochure.
Excellent
Light returns through the top. This is the C that makes a diamond look alive.
H
Near-colorless. Most eyes stop noticing here, especially in yellow gold.
SI
Usually clean to the eye. We still loupe it before a prong covers, or doesn’t.
1.00 ct
Weight, not face-up size. A well-cut 0.90 often looks larger than a heavy 1.00.
Order of importance
GIA set the language in the 1940s. In the workshop, cut still leads. Color and clarity follow. Carat is the number people ask for first, and the one that should come last.
Color
D is icy. Z is warm. G–J is the value lane. Yellow gold hides tint. Platinum shows it.
Clarity
Eye-clean is what you wear. VS2–SI1 is often enough. A well-placed prong can cover a spot the grade can’t.
Carat
One carat is 200 milligrams. Buy just under the round numbers. Spread and cut decide how large it looks.
How we buy
-
Pay for cut.
If the budget is tight, keep cut at Excellent or Very Good. Dull is dull in any mounting.
-
Stop at eye-clean.
SI1 is often the last grade that still looks clean without a loupe. After that, you’re paying for a certificate.
-
Match metal to color.
H–J in yellow gold. D–G if the head is platinum. Step cuts (emerald, Asscher) show color more than brilliants.
-
Bring the paper.
GIA or IGI. We set natural and lab-grown the same way. The stone still has to sit true.
Questions
Which of the 4 Cs matters most?
Cut. It has the most to do with sparkle. The “most important” C after that is whatever you notice first: size, icy white, or a clean face.
What’s a smart combination?
Excellent cut, color G–J, clarity VS2–SI1, then as much carat as the budget allows. That reads clean, bright, and the right size in the hand.
Do you set lab-grown diamonds?
Yes. Same carbon, same 4 Cs, same prongs. Natural or lab. The setting work does not change. The lab vs natural guide covers origin, price, and paper.
Should I bring a certificate?
If you have one, yes. GIA and IGI are what we see most. We still look at the stone, not only the paper, before we set it.
Have the stone. We’ll make it hold.
31 West 47th Street, Suite 1105 · Monday–Friday, 9 to 5. Walk-ins welcome.