LEARN ABOUT DIAMOND CARAT
A carat is a unit of weight for diamonds
and other gems. The metric carat of .200 grams, or 200 milligrams was
adopted in the United States in 1913 and now standardized in the principle
countries of the world.
The weight of a diamond is numerically expressed in carats. Diamond
weight is subdivided further into smaller units commonly referred to as
points. A point(s) is a scale of weight that is equal to .01 carat. A one
carat diamond is made up of 100 points. The term point(s) does not refer to
the amount of facets or individual flat surfaces a diamond possesses as its
definition is sometimes incorrectly interpreted.
A diamond that weighs .50 carat or 50 points would be considered 1/2 carat
in size. A diamond that weighs 1.00 carat or 100 points is considered a
carat. A two carat diamond would weigh 2.00 carats, 200 points or 400
It is very important that one does not relate the numerical values of
carat weight as a judgment of a diamonds actual diameter size. Because
carat weight is a numerical value of weight, it is therefore possible for a
diamond with smaller diameter to weigh the same or more than a diamond with
a larger diameter. This is done by making the smaller diamond deeper or
thicker and the diamond with the larger diameter is made shallower or
thinner. See Diagram to the right.
Because many people buying diamonds today have the expertise to identify a
inferior cut diamond, many of the diamonds sold on the market today
have inferior cut. Diamond cutters have a substantial financial incentive
not to remove any more weight from the rough diamond crystal than they feel
is necessary to sell the diamond. Because cutters are able to deliver a
heavier diamond from a smaller rough diamond crystal, he is able sell the
diamond for less and make more profit. For example: an ideal or very fine
cut one carat diamond will measure 6.4 to 6.5 millimeters. If you were
to measure the diameters of most one carat diamonds on the market today, you
would find most to be measure between 5.9 and 6.3 millimeters. These
inferior cut, “undersize diamonds” would have only the diameter of
ideal cut or fine cut diamonds that weighs .75 to .99 carats. These diamonds
are not truly a one carat from the standpoint of diameter and acceptable
You must also realize that a degree of brilliance is scarified when diamonds
are produced with inferior cut. Comparing a Ideal cut or very fine cut
diamond to an inferior cut diamond is similar to comparing a 100 watt light
to a 50 watt light. The 50 watt looks ok until it is compared to the 100
watt light. The diagram above illustrates the path light takes through a
inferior and and ideal cut.
“Undersize inferior cut diamonds” are abundant in all size ranges and
are commonly sold with GIA, EGL and IGI and other diamond quality reports.
Because GIA, EGL, IGI and other gemological laboratories do not assign a
overall cut grade, it is up to the individual to know a diamonds depth
percentage, table percentage, girdle thickness, culet, polish, symmetry and
more. Please refer to detailed information contained in the previous page
that describes details of a properly cut diamond.