A Guide to Diamonds

A Guide to Diamond Color

When evaluating a white diamond, color is the absence of it. GIA grades that absence from D to Z — table-down, against masterstones, in controlled light. Face-up in a ring, D through F are the same conversation.

The GIA color grades

• D–F

  Colorless

  No visible color. Graded table-down against masterstones in controlled light. The difference between D and F is a laboratory distinction — not a face-up one in a finished ring.

• G–J

  Near colorless

  Looks white when set. G–H is where most of our clients land. I–J take yellow or rose gold beautifully, and cost less for the same size and cut.

• K–M

  Faint

  Warmth you can see, especially above a carat. Not a defect — a temperature. We use it when the metal and the skin tone want it.

• N–R

  Very light

  Color is part of the stone’s character. Rarely what someone means when they say they want a white diamond.

• S–Z

  Light

  Obvious body color. Past Z, GIA grades diamonds as fancy yellow, brown, or another hue — a different (and often more valuable) conversation.

Platinum and white gold show color. Yellow and rose gold hide it. Most of the rings we make live in G–H for white metal, I–J for yellow. Past Z, GIA grades fancy color — a different book.

Colorless · D

DEFGHIJKLMNOPQRSTUVWXYZ

Absolutely colorless. The rarest white. Visible only beside a masterstone, table-down.

Touch a grade to hold

A Guide to Diamond Clarity

Clarity is a map of the crystal. Inclusions inside, blemishes outside. GIA assigns eleven grades at 10×. On the hand, FL and VS2 can be the same picture. We ask if it is eye-clean — then we put the loupe away.

The GIA clarity chart

• FL

  Flawless

  No inclusions or blemishes visible to a skilled grader using 10× magnification. Exceptionally rare. A collector’s grade, not a beauty grade — FL and IF look identical on the hand.

• IF

  Internally Flawless

  No inclusions at 10×. Only blemishes are visible to a skilled grader using 10× magnification. Same face-up silence as Flawless.

• VVS1

  Very, very slightly included

  Inclusions so slight a skilled grader has difficulty seeing them at 10×. Invisible in a ring. Pays for a laboratory distinction.

• VVS2

  Very, very slightly included

  Still extremely difficult at 10×. We buy VVS when the stone is large, step-cut, or the client wants the paper to match the quiet of the diamond.

• VS1

  Very slightly included

  Minor inclusions, visible to a grader with effort. Eye-clean in virtually every shape. A professional’s default for important stones.

• VS2

  Very slightly included

  Minor inclusions, still typically eye-clean in rounds. The last grade we treat as ‘always silent’ before we start looking with the naked eye.

• SI1

  Slightly included

  Noticeable at 10×. Many rounds are still eye-clean. We always view SI1 in person — location matters more than the letters.

• SI2

  Slightly included

  More obvious at 10×. Some are beautiful; some are not. Never buy SI2 off a report. The plot and the loupe decide.

• I1

  Included

  Obvious inclusions under 10× that may affect transparency or brilliance. Occasionally usable in a halo or a small side stone. Not our center-stone default.

• I2

  Included

  Inclusions obvious to the unaided eye. Brilliance and sometimes durability suffer.

• I3

  Included

  Inclusions that seriously affect appearance and often durability. We do not set I3 as a featured stone.

Flawless · FL

FLIFVVS1VVS2VS1VS2SI1SI2I1I2I3

No inclusions or blemishes visible to a skilled grader using 10× magnification. Exceptionally rare. A collector’s grade, not a beauty grade — FL and IF look identical on the hand.

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A Guide to Diamond Cut

Cut is the only C that is a craft. It is what turns carbon into light — brightness, fire, scintillation. GIA grades Excellent through Poor on round brilliants. Fancy shapes receive polish and symmetry. We start every conversation here.

The GIA cut grades

• EX

  Excellent

  Returns nearly all light as brightness, fire, and scintillation. GIA’s top cut grade for standard round brilliants. This is where we start.

• VG

  Very Good

  Slightly less light return than Excellent. Often indistinguishable on the hand. A legitimate value choice when the other three Cs are right.

• G

  Good

  Noticeable compromise in pattern or brightness. We rarely recommend Good as a center stone. The money is better spent on a smaller Excellent.

• F

  Fair

  Light leaks. Often a dark center (too deep) or a glassy ring (too shallow). The stone looks smaller and duller than its carat weight.

• P

  Poor

  Cut to save weight, not to perform. A carat number with no life.

Excellent

ExcellentVery GoodGoodFairPoor

Returns nearly all light as brightness, fire, and scintillation. GIA’s top cut grade for standard round brilliants. This is where we start.

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A Guide to Diamond Carat

Carat is weight, not size. A metric carat is 200 milligrams. A 0.99 and a 1.00 can look the same. The price does not. Buy spread, not a number — a well-cut oval of 1.00 ct often reads larger than a deep round of 1.20 ct.

1 ct · 6.5 mm

0.250.500.7511.52345

One carat. A psychological line. A 0.90 Excellent often looks the same and costs less.

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A Guide to Fluorescence

Not a 4C — an identifying characteristic. GIA reports None, Faint, Medium, Strong, Very Strong under long-wave UV. About three in ten natural diamonds glow. Almost always blue. None and Faint never change the conversation. Strong we take to a window.

Daylight

Long-wave UV

None

NoneFaintMediumStrongVery Strong

No reaction under long-wave ultraviolet. The most common report line. Neither better nor worse — the stone is quiet in sun and in a lamp.

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A Guide to Diamond Certification

Diamond certification is how you evaluate quality, integrity, and origin before a stone is set. A grading report lists the 4Cs, the measurements, fluorescence, and a plot. We still sit with the diamond. We still verify the report number on the laboratory’s own site. We still read the comments line — where treatments, clouds, and inscriptions hide.

Gemological Institute of America

Established in 1931, GIA is a public-benefit institute. It wrote the 4Cs so a diamond could be described without theatre. We prefer GIA for natural diamonds. For laboratory-grown, GIA or IGI, with the origin in plain language.