Diamond Education
“Everything you need to know before you buy.”
We believe an informed buyer is a confident buyer. This guide covers everything from the four Cs to reading a GIA report.
The Most Important C
The only grade that determines how much your diamond dazzles.
Cut is the single most important of the four Cs — and the only one entirely controlled by human craftsmanship. It refers not to the shape of a diamond, but to how well its facets interact with light. A well-cut diamond reflects light internally from one facet to another, then disperses it through the top of the stone as brilliance (white light), fire (rainbow flashes), and scintillation (sparkle).
The GIA grades cut on a five-point scale: Ideal, Excellent, Very Good, Good, and Fair. At Tessera, we only carry Excellent and Ideal cut diamonds. Anything below that standard, regardless of how impressive the carat weight or color grade looks on paper, will not meet our criteria.
The practical implication is significant: two diamonds of identical carat weight, color, and clarity can look dramatically different simply because of how they were cut. Cut is what separates a lifeless stone from one that commands a room.
Cut Grade · Relative Brilliance
Cut quality measures proportions, symmetry, and polish — all three interact to determine how much light escapes back through the top versus leaking out the sides or bottom.
The D-Z Color Scale
D – F · Colorless — the rarest and most desirable tier.
G – H · Near colorless — our sweet spot for value and beauty.
I – Z · Faint to light yellow — visible warmth in the stone.
The Subtle Spectrum
The difference between D and Z is real — but not always visible.
A diamond’s color grade measures the absence of color. The GIA color scale runs from D (completely colorless) to Z (light yellow or brown tint). The differences between adjacent grades are often invisible to the untrained eye — but they matter, and they’re reflected in price.
D, E, and F are the colorless tier: chemically pure and structurally perfect. They command a premium, especially for larger stones where color becomes more perceptible. G and H are near-colorless — they’ll look completely white when set in most metals, including white gold and platinum, and they represent exceptional value relative to their appearance.
At Tessera, we focus on D through H. Below H, color becomes discernible, particularly in stones over one carat or when set in white metals that amplify any warmth in the diamond. In a yellow or rose gold setting, however, G-H can be virtually indistinguishable from D-F while saving significantly on cost.
Flawless to the Eye
Nature leaves its mark. The question is whether you can see it.
Clarity refers to the presence — or absence — of inclusions and blemishes in a diamond. Inclusions are internal characteristics: tiny crystals, feathers, or clouds formed during the diamond’s growth over billions of years underground. Blemishes are surface imperfections introduced during cutting or handling. The GIA clarity scale has 11 grades from Flawless to I3.
The key concept for buyers is “eye-clean” — a diamond that shows no visible inclusions to the naked eye when viewed from about a foot away. This threshold typically starts at VS2 and extends through VS1, VVS2, VVS1, IF, and FL. You do not need a Flawless diamond to have a visually perfect diamond.
SI1 can occasionally be eye-clean, but it requires careful review of the GIA plot to confirm inclusions aren’t centrally located. SI2 and below often have inclusions visible without magnification. At Tessera, we recommend VS2 or better as our standard — every stone at that grade and above will be eye-clean, guaranteed.
GIA Clarity Scale
FL
Flawless
IF
Internally Flawless
VVS1 / VVS2
Very Very Slightly Included
VS1
Very Slightly Included 1
VS2
Very Slightly Included 2
SI1
Slightly Included 1
SI2
Slightly Included 2
I1 / I2 / I3
Included — visible to naked eye
Grades above VS2 are eye-clean by definition. Stones graded FL–VVS command a premium for their rarity, not visible appearance — the differences require 10× magnification to detect.
Relative Size · Top-Down View
These sizes represent ideal-cut round brilliants viewed from above. Actual face-up diameter depends on cut proportions — two diamonds of the same carat weight can have visibly different face-up sizes based on how deep or shallow they were cut.
A 1.0ct round measures approximately 6.4–6.5mm in diameter. A 0.9ct Ideal cut may measure 6.3mm — nearly indistinguishable, at a meaningful price difference.
Size Is Just the Beginning
Carat is weight, not size. The distinction matters.
Carat is the unit of weight used for diamonds — one carat equals 0.2 grams. It’s commonly confused with size, but carat is a measure of mass, not diameter. A well-cut diamond will show more of its carat weight face-up, while a poorly-cut stone may appear smaller than a lighter diamond of better proportions.
Price increases non-linearly with carat weight. A 1.0ct diamond is significantly more expensive than two 0.5ct diamonds of equal quality — demand for “magic numbers” (1.0ct, 1.5ct, 2.0ct) creates price jumps at those thresholds. Stones just below the threshold (0.9ct, 1.4ct) often offer the same visual presence at a 10–20% price reduction.
When working with a budget, think about carat as the last variable to adjust — after you’ve locked in an Excellent cut and a clarity grade you’re satisfied with. A smaller stone that maximizes light performance will look more impressive than a larger stone that sacrifices brilliance for size.
The GIA Standard
“Why every Tessera diamond is GIA certified.”
The Gemological Institute of America is the world’s foremost authority on diamonds, gemstones, and pearls. Founded in 1931, the GIA created the 4 Cs grading system and the International Diamond Grading System that the entire industry uses today. When you see a GIA certificate, you’re looking at the most rigorous, independently verified grading report available — produced by gemologists with no financial stake in the sale of the stone.
A GIA Diamond Grading Report documents every measurable characteristic of a stone: its weight, dimensions, cut grade, color grade, clarity grade, polish, symmetry, and fluorescence. It includes a plotting diagram showing the exact location of any inclusions, and a unique certification number that can be verified on the GIA’s public database at any time. The report travels with the diamond and gives you complete, permanent documentation of exactly what you purchased.
For buyers, the practical value of a GIA certificate is straightforward: it removes all uncertainty from the transaction. Without independent certification, you’re relying entirely on the retailer’s characterization of the stone. With a GIA report, the grade is the grade — confirmed by a lab with no incentive to flatter your diamond. At Tessera, every stone we list is GIA certified, every report is included with your purchase, and the certification number is listed on every product page so you can verify before you buy.
Diamond Grading Report
6417 8829 03
Shape & Cutting Style
Round Brilliant
Measurements
6.47 – 6.50 × 4.01 mm
Carat Weight
1.02 carat
Color Grade
E
Clarity Grade
VS1
Cut Grade
Excellent
Polish
Excellent
Symmetry
Excellent
Fluorescence
None
Depth %
61.8%
Table %
57%
Girdle
Thin – Medium, Faceted
Verify or learn more from independent sources:
- GIA Report Check — verify any GIA or IGI grading report by its certificate number.
- GIA 4Cs of Diamond Quality — the original source of the grading system.
- IGI Report Verification — verify International Gemological Institute reports (common for lab-grown diamonds).
- GIA on Lab-Grown Diamonds — independent explanation of how lab-grown diamonds are created.
Find Your Shape
“8 shapes. 8 personalities.”
Round
Most brilliant · Timeless · The world’s most popular cut
Oval
Flattering · Elongating · Looks larger than its carat weight
Princess
Modern · Architectural · Sharp, geometric brilliance
Cushion
Romantic · Vintage · Soft corners, pillow-like warmth
Emerald
Cool · Understated · Long, open facets for a hall-of-mirrors effect
Pear
Distinctive · Feminine · The teardrop of diamonds
Marquise
Dramatic · Elongating · The most finger-flattering of all shapes
Radiant
Versatile · Vibrant · Brilliant facets in a classic square form
Before You Buy
“Five things every buyer should know.”
Prioritize cut above everything else.
Cut is the only C that humans control. The other three — color, clarity, and carat — are characteristics nature determined. But cut is craftsmanship, and craftsmanship is the difference between a diamond that stops people in a room and one that simply exists in a setting. A great cut creates brilliance, fire, and scintillation; no other grade can compensate for a poor one. When in doubt, go Excellent or Ideal and work backward from there.
Always buy GIA certified.
The GIA is the most respected independent grading laboratory in the world, and its certificates are impossible to fake — every report can be verified directly on GIA’s public database with the certificate number. Other labs exist, and some are reputable, but none match GIA’s consistency and credibility. Without an independent GIA report, you are trusting the seller’s characterization of the most important details. That’s a risk you don’t need to take.
Go eye-clean on clarity.
You do not need a Flawless diamond. The difference between FL and VS2 is visible only under 10× magnification — which means it’s invisible in everyday wear, in photographs, and in any normal viewing situation. VS2 inclusions are imperceptible to the naked eye at any viewing distance. By limiting your search to VS2 and above, you get a visually perfect diamond while preserving budget for a better cut or larger stone where the difference is actually visible.
Color is personal — and metal-dependent.
In a white gold or platinum setting, D–F is ideal because the cool metal doesn’t introduce any warmth of its own — any faint color in the diamond would be visible by contrast. But in yellow gold, G–H is nearly indistinguishable from D–F, because the warm metal tone masks any subtle warmth in the stone. If yellow gold is your setting of choice, prioritizing cut and clarity over the top color grades is often far better value. The eye cannot reliably distinguish G from D in most real-world settings.
Set a budget range, not a fixed number.
Diamond pricing is granular. A $100 difference can separate a mediocre stone from a meaningfully better one — or it can represent the difference between a VS2 and a VS1 that look identical in person. Buyers who arrive with rigid fixed budgets often miss the stone that was right for them by a small margin. Instead, define a comfortable range within 10–15% of your target. Approach the search with flexibility, prioritize cut quality first, and let the other variables balance within that window. The right stone is rarely the one that lands exactly on a round number.
Ready to find
your diamond?
Every stone in our collection is GIA- or IGI-certified, Triple Excellent, and ready to ship.