Close-up of the letters R.D.I. laid out in loose diamonds on black velvet

The 4Cs

Look closely and no two diamonds are alike.

Over the years, the trade has settled on one universal standard for describing them. It rests on four characteristics that decide quality and value: carat, clarity, colour and cut.

Tweezers holding a diamond above loose diamonds of different sizes

Carat

Carat tells you what the stone weighs.

1 carat = 0.2 grams = 100 points

  • .05
  • .10
  • .15
  • .20
  • .25
  • .50
  • .75
  • 1.00
  • 1.25
  • 1.50
  • 1.75
  • 2.00
  • 2.50
  • 3.00
  • 4.00
  • 5.00 ct
A grader examines a diamond through a loupe

Clarity

Nature leaves traces of growth in every diamond it makes.

Clarity is how we describe the stone’s purity.

  • Clarity plot, IF
    IFInternally Flawless
  • Clarity plot, VVS1
    VVS1Very Very Small Inclusions
  • Clarity plot, VVS2
    VVS2Very Very Small Inclusions
  • Clarity plot, VS1
    VS1Very Small Inclusions
  • Clarity plot, VS2
    VS2Very Small Inclusions
  • Clarity plot, SI1
    SI1Small Inclusions
  • Clarity plot, SI2
    SI2Small Inclusions
  • Clarity plot, I1
    I1Inclusions
  • Clarity plot, I2
    I2Inclusions
  • Clarity plot, I3
    I3Inclusions
Loose diamonds on a white grading surface

Colour

Most diamonds range from colourless to a faint, warm yellow.

A perfect diamond shows no colour whatsoever.

  • DExceptional White+
  • EExceptional White
  • FRare White+
  • GRare White
  • HWhite
  • ISlightly Tinted White+
  • JSlightly Tinted White
  • KTinted White+
  • LTinted White
  • MTinted Colour
  • N–OTinted Colour
  • P–RTinted Colour
  • S–ZTinted Colour

Cut

A diamond’s beauty comes through its cut.

The cutter sets its proportions, symmetry and polish. Each of the three receives a grade of Excellent, Very Good, Good or Fair.

  • Proportions diagram: table width, crown height and angle, girdle, pavilion depth and angle, total depth, culet
    Proportions
  • Polish diagram
    Polish
  • Symmetry diagram
    Symmetry
  • Diamond shapes
    Shape

Put your diamond under our loupe.

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