Color
Grading Scale
The Color
Grading Scale: ranges from totally colorless to fancy yellow.
The differences between one grade and another are very subtle,
as can be seen by the number of grades within any one category.
Diamonds are
graded for color only as loose, unmounted stones in the inverted
position (table down, pavilion up),
and under very specific conditions of lighting and background,
and also the distance and angle of the observer in relation to
the stone.
A color scale has been devised by the Gem Trade Lab. of the Gemological
Institute of America (GIA)
divided alphabetically from D (the absence of color) to Z (fancy
yellow color), and is recognized world-wide.
Each letter grade represents a small range of color, and not just
a single color.
Diamonds are color graded by being compared to a set of master
stones.
| D
E F |
Colorless |
| G
H I |
Nearly
colorless (not distinguishable from colorless when mounted) |
| J
K L |
Slightly
yellow (color distinguishable to the trained eye) |
| M
N O |
Light
yellow |
| P
Q R S T U V W X |
Darker
yellow |
| Z |
Fancy
colors |
Even though
there are several grades in each category, there are slight differences
between the letter grades.
D is the clearest and most valuable, X is a dingy
yellow and least expensive.
Z grade-colored diamonds are the rarest and most expensive.
A diamond so saturated with nitrogen that it becomes a deep, rich
yellow is as rare as a colorless diamond.
|
shape & carat | clarity
scale | color scale | cut
|
