"The weight or size of a diamond is measured in carats (ct.). One carat weighs 1/5
of a gram and is divided into 100 points, so a diamond weighing 1.07carat is referred
to as "one carat and seven points."
0.75 carat = 75 points.
1/2 carat = 50 points.
1/4 carat = 25 points.
When diamonds are mined, large gems are discovered much less frequently than small
ones, which make large diamonds much more valuable.
Diamond prices rise exponentially with carat weight. So, a 2-carat diamond of a
given quality is always worth more than two 1-carat diamonds of the same quality.
Most diamonds of gem quality used in jewelry vary in shade from completely colorless
down to a visible yellow or brown tint.
The rarest and most expensive are diamonds in the colorless range graded D,E and
F on a scale that descends to Z. Diamonds with more color than Z, or in other shades
such as orange, pink, blue, etc. are classified as "Fancy Colored Diamonds"
Since diamonds form under extreme heat and pressure, internal and external characteristics
are common. These characteristics help gemologists separate natural diamonds from
synthetics and simulants, and identify individual stones. clarity characteristics
marked in red for internal, and green for external features; they are useful for
I.F. : Internally Flawless
Free of inclusions. Only insignificant blemishes visible under 10x magnification.
VVS1 - VVS2 : Very Very Slightly Included
Minute inclusions that are very difficult to locate under 10x magnification.
VS1 - VS2 : Very Slightly Included
Minute inclusions that are difficult to somewhat easy to see under 10x magnification.
SI1 - SI2 : Slightly Included
Noticeable inclusions that are easy to see under 10x magnification.
I1 - I2 - I3 : Included
Inclusions that are obvious to a trained grader under 10x magnification and can
be easily seen face-up with the unaided eye.
While nature determined the color and clarity of a natural diamond, man is responsible
for the cut quality which brings it to life.
The planning, proportions, cutting precision and details of finish determine how
brilliant, dispersive and scintillating the diamond will be. If the cutting factors
under man's control are not optimized, the appearance of the diamond can be adversely
Diamond faceting has changed over time, particularly as lighting has evolved. There
are many shapes and cutting styles, each with different visual properties. The most
popular diamond in the age of modern electric lighting is the Round Brilliant.