Colored Stone Grading Methodology

Carat Weight

Shape and Cutting Style

Measurements (length x width x depth: in millimetres)

Colour

  • Hue
  • Saturation (weak-fair-moderate-strong)
  • Tone (very light-light-medium-dark-very dark)
  • Colour zoning (none-faint-moderate-strong)
  • Pleochroism (none-faint-moderate-strong)
  • Fluorescence (none-faint-moderate-strong)
  • Poor-Fair-Good-Very Good-Excellent

CLARITY

  • Flawless
  • Lightly included
  • Moderately included
  • Visibly included
  • Heavily included

CUT

  • Brilliance (poor-fair-good-very good-excellent)
  • Total depth percentage (depth/width: in millimetersx100)
  • Crown-to-pavilion ratio (1:2-1:3-1:4-1:5-1:6)
  • Length-to-width ratio (length/width: in millimetres)
  • Pavilion bulge (none-slight-moderate-large)
  • Girdle thickness (very thin-thin-medium-thick-very thick)
  • Symmetry (poor-fair-good-very good-excellent)
  • Finish (poor-fair-good-very good- excellent)
  • Poor-Fair-Good-Very Good-Excellent