Grading Color (Chapter 13, Key Terms & Key Concepts) Flashcards
The basic face-up color of a
colored diamond.
Characteristic color
A position that orients
a gemstone’s pavilion toward the viewer.
Face-down (or table-down)
A position that orients a
gemstone’s crown toward the viewer.
Face-up (or table-up)
The optical illusion that causes
the ungraded diamond to appear either lighter or
darker than the masterstone, depending on which
side it’s on.
Master-eye effect
A set of color-comparison diamonds
that defines GIA diamond color grades in the normal
(D-to-Z) range.
Masterstones
Slight color differences can equal large value differences.
Key Concept
The GIA diamond color-grading system is the universal
standard in the jewelry industry.
Key Concept
Each letter on the scale represents a narrow range of color,
and each masterstone marks the least amount of color in that
range.
Key Concept
The biggest price difference occurs between the D and E
grades, all other factors being equal.
Key Concept
The GIA color-grading system helps diamond professionals
communicate accurately about diamond color.
Key Concept
The color-grading environment should affect the color grade
as little as possible.
Key Concept
The most widely accepted lighting for color-grading diamonds
is balanced, daylight-equivalent, fluorescent light.
Key Concept
The set of masterstones should be matched to the specific
color-grading requirements of the user.
Key Concept
The masterstones and the diamond to be graded must be
clean for best results.
Key Concept
The masterstones and the diamond to be graded must be
clean for best results.
Key Concept
It’s possible to estimate diamond color, and the results can
be fairly accurate
Key Concept
Proportion variations, size, and clarity characteristics can
influence a diamond’s color appearance.
Key Concept
Cut can influence the color of colored diamonds, so they’re
graded face-up.
Key Concept
The goal of colored diamond color grading is to arrive at a
repeatable, consistent grade.
Key Concept
Subtle color differences are usually more visible when seen
through the pavilion.
A loose brown diamond should be color-graded
in the normal color range./retest
Which of the following GIA color grades indicates the greatest amount of yellow?
H
Which of the following makes a diamond unsuitable for a masterstone set?
crowns and pavilions must not be shallow or deep./retest
The diamonds used as comparison stones for color grading are called
masterstones.
Colorless diamonds are more valuable than others in the normal color range because they
are more rare.
The most widely accepted lighting for color-grading diamonds is
balanced, daylight-equivalent fluorescent light.
The color grade of a diamond that appears darker than the H masterstone but lighter than the I would be
H.
When color-grading with masterstones, you should
grade table down through the pavilion/retest
Trade terms that describe diamond color
can be misleading.
If a diamond has a slight tint in the face-down position and appears colorless in the face-up position, its estimated color grade would be
G, H, I, or J.
GIA Gem Trade Laboratory uses a Z masterstone to determine fancy
yellows.
Diamonds outside the normal color range are graded
face-up.
The basic face-up color of a colored diamond is known as its
characteristic color/retest
A masterstone graded as whole grade represents the
the least amount of color possible in that grade’s range./retest
