A carat is a unit of measurement used to weigh a diamond. One carat is equal to 200 milligrams. Carat weight is normally referred to in points. One carat consists of 100 points. For example, .50 carats can be labeled as 50 points or 1/2 of a carat. Carat weight is the most important factor when calculating the value of a diamond. However due to higher or lower quality ratings, diamonds of equal carat weight can often be worth considerably more or less than it's equal weight counterpart.
Diamonds come in a wide array of colours which based on it's rarity, will effect a diamonds value. The most common scale used to rate a diamonds colour is an alphabetical scale starting at the colour D. This is the whitest or purest colour possible in a diamond, also known as pure white.
Of course diamonds rated closest to the top of this scale are appraised at a higher value than those with a yellow tint.
Note that fancy colour diamonds are very rare and very expensive, and range in colour from blue to green to bright yellow. They are actually more valuable for their colour.
As is commonly thought, a diamonds cut does not refer to it's shape.
A diamonds cut actually refers to it's depth and width, and the uniformity of it's facets.
The brilliance of a diamond is heavily dependent on how well the diamond is cut.
A well cut stone will display the fiery colours from deep within the diamond by enabling
the maximum amount of light that enters through the table to be reflected back through
the table and to the viewer. A poorly cut diamond will absorb light through the diamonds
table and emit the light through the sides, rather than reflecting it back through the top
of the diamond. This lower level of reflected light ultimately effects the diamonds sparkle
FLAWLESSNo internal or external flaws. Extremely rare.
INTERNALLY FLAWLESSInternally flawless diamonds contain only external flaws which can usually be made flawless with minor re-polishing.
VVS1, VVS2These grades might contain minor inclusions so small or so insignificant that they are difficult to locate under 10x.
VS1, VS2These grades might contain minor inclusions of a size, number and location between those difficult to locate and those somewhat easy to locate under 10x.
SI1, SI2These grades contain noticeable inclusions which are easily visible under 10x. Normally the inclusions will be centrally located and noticed immediately when the stone is examined.
I1, I2, AND I3The imperfect categories contain inclusions which are obvious when viewed under 10x and which may be visible to the unaided eye in the face-up position.