Diamond
Grading Terminology
A diamond's cost is based on the characteristics known as the "4
C's". Clarity, Color and Cut (proportion) are the quality elements which
together with the Carat Weight determine the value of a stone. The closer a
diamond grades to the left of one or all of these scales the rarer and the
more costly it will be. While clarity is frequently assumed to be the most
important factor of all the "C's", in fact, color and cut
(especially cut) have a more profound affect on the visual appearance of a
diamond.
Clarity
A diamond's clarity is determined by the number, nature, position, size and
color of internal characteristics called "inclusions" and surface
features called "blemishes". These irregularities occurred in the
liquid magna (volcanic rock) within which the diamond was created. Diamonds
are mostly pure carbon, however, during crystallization other minerals
nearby, or even other bits of carbon forming more quickly may have become
trapped within the cooling mass. These show themselves as the various
characteristics which make up the clarity of a diamond (included crystals,
feathers, clouds etc). Clarity is measured on a scale ranging from pure
(flawless) to heavily included (I-3). The clarity of a diamond is graded by
using 10X magnification under good lighting by an experienced grader. The
final clarity grade is usually determined by how easy the inclusions and
blemishes are for the grader to see.
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Color
Ideally, a diamond should have no color at all, like a drop of spring water.
Increasing degrees of body color are measured on a scale ranging from no
color at all (D) to deeply colored (Z). Beyond "Z" is the range
where the diamond's color is vivid and rich, called "fancy colors".
Diamonds of known color are used as comparison stones for color grading.
Grading is done by comparing the diamond to be graded against these
"master stones" under either artificial or natural north daylight
(in the Northern Hemisphere). A machine called the "Colorimeter"
can be used for color grading but there is no substitute for the trained
human eye.
![](Diamond%20Grading%20Terminology_files/image002.gif)
Cut
Cut, sometimes the forgotten "C", ensures that a given stone
has maximum brilliance and sparkle which would not be the case were the stone
cut for weight alone.We use the following scale to grade a stone on it's
overall appearance.
Angles and percentages are
for diamond cutters and graders. Simply put, when looking at a diamond, if it
doesn't catch your eye or if it doesn't flash in the light, it's probably not
well cut. Good cutting is what brings fire to the ice.
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