Diamond Grading Information
The Four C's
The first C is cut.
Cut refers to the proportions, dimensions, and quality of the workmanship of the cutter. When properly cut, a diamond will use light to its best advantage for maximum beauty and flash. Poorly cut stones will let light escape though the sides and bottom of the stone.
[ideal cut]
Parts of the Cut
The standard brilliant cut has 32 facets plus a table above the girdle and 24 facets plus a culet below the girdle.
Term Description
Bezel Facets The facets between the girdle and the table
Brilliant A type of cut that has few or no facet edges in parallel
Crown The portion of the stone above the girdle plane, the top portion
Culet The tiny facet at the bottom of the stone parallel to the table
Facet Any one of the flat, polished faces of a cut gemstone.
Girdle The perimeter around the outside edge of the stone
Pavilion The portion of the stone below the plane of the girdle, the bottom portion.
Table The top facet of a stone
The second C is Color
Color in white diamonds is graded based on the lack of any color. The G.I.A. grading scale goes alphabetically from color "D", totally colorless, to color "Z" light yellow. Of course, colorless is the most sought after "white" diamond. Beyond "Z" fancy color yellows and browns can be quite desirable.

Colors D-F will nearly always appear colorless. Colors G-l will usually appear colorless. Colors J-L will look colorless in small stones, but larger stones will appear tinted. Anything over L will generally appear to have color even to the untrained eye.

GIA Color Grade Description
D colorless
E practically colorless
F practically colorless
G nearly colorless
H nearly colorless
I nearly colorless
J nearly colorless
K faint yellow or brown
L faint yellow or brown
M faint yellow or brown
N very light yellow or brown
O very light yellow or brown
P very light yellow or brown
Q very light yellow or brown
R very light yellow or brown
S-U very light yellow or brown
V-W light yellow or brown
X-Z light yellow or brown
The third C is Clarity
The clarity grade expresses the degree to which the stone contains surface blemishes, or internal flaws called inclusions. Generally, and particularly with diamonds, the lack of these features is the most desirable condition. Inclusions can be all sorts of things: breaks, other crystals, clouds, growth lines, bruises, and pinpoints. Blemishes include: extra facets, pits, cavities, chips, nicks, abrasions, and scratches. Grading is done under 10 power magnification and proper lighting.
Clarity Grade Description
Flawless No inclusions or surface blemishes
IF Internally flawless, insignificant blemishes
VVS1 extremely difficult to see at 10x
VVS2 very difficult to see at 10x
VS1 difficult to see face up at 10x
VS2 somewhat easy to see face up at 10x
SI1 noticeable, easy to see at 10x
SI2 very easy to see at 10x, may be visible to the unaided eye
I1 obvious at 10x, visible to the unaided eye.
I2 obvious at 10x, easily visible to unaided eye, beauty/durability somewhat affected
I3 prominent inclusions, extremely easy to see with unaided eye, durability affected

With all the C's being equal except for the clarity, there is a big difference in the price of a stone. This same principle applies to the other graded characteristics as well. For example, let's consider a half-carat (.50ct) round brilliant cut, color F diamond. With only the clarity grade changing, here is how that stone's price per carat may vary:

  • $10,000 for IF ( Internally Flawless )
  • $8,800 for VVS1
  • $7,000 for VVS2
  • $6,800 for VS1
  • $5,000 for VS2
  • $4,400 for SI1
  • $3,600 for SI2
  • $2,800 for I1
  • $1,900 for I2
The fourth C is Carat Weight
The term "carat" is used to express gemstone weight. One carat is a fifth of a gram. A carat is further subdivided into points. There are 100 points in a carat (one point = .01 carats) .