When buying a diamond there are four things you need to know. Those four things are called the 4 Cs which refer to the cut, color, clarity and carat weight of the diamond. The combination of the 4 Cs is what determines the quality and hence the rarity of each diamond. These four factors are what determine the price you pay.
Note: My goal here is to explain things to you in plain everyday language. I'm not trying to dazzle you with fancy words. I will use trade jargon sparingly and only as necessary. You will be able to find more technical explanations in other areas throughout this website. Let's begin.........
Cut refers to the proportions of the diamond and the arrangement of its
facets. Do not confuse cut with the shape of the diamond. Cut is the
most important of the 4 Cs. This is what determines the amount of
brilliance as well as spectral colors of the rainbow the diamond will display.
Color refers to the diamond's natural tint or bodycolor. The most common
colors are yellow, brown and gray. The color scale runs from D
(colorless, the highest and rarest grade) to Z (light yellow, brown or
gray). This scale is broken down into five groups:
D-E-F - colorless
G-H-I-J - near colorless
K-L-M - faint yellow, brown or gray
N-O-P-Q-R - very light yellow, brown or gray
S-T-U-V-W-X-Y-Z - light yellow, brown or gray
(Note: each letter grade of the color scale has its own range within the scale.)
Clarity refers to the diamond's internal characteristics and surface
blemishes. (I also like to refer to them as the diamond's fingerprints
or birthmarks. Just like people, no two diamonds will ever have the
same fingerprints or birthmarks.)
Carat weight refers to the actual weight of the diamond which is weighed on a
gemstone scale. Don't confuse carat weight with the size of the
diamond. Two diamonds can have the same carat weight but look
dramatically different in size based on the proportions of the
diamond. As stated above, this is due to the "cut" of the diamond.
Carat weight is expressed as follows: (Just like there are 100 pennies in a dollar, there are 100 points per carat.) So one point, expressed as 0.01carat equals 1/100th of a carat.
one quarter carat = 0.25 ct
one half carat = 0.50 ct
three quarters carat = 0.75 ct
one carat = 1.00 ct
Carat Weight
Photos above are not to scale.
Note: Carat weight is a measurement of weight not size. Remember, two diamonds can be the same carat weight but appear to be different sizes depending on how well proportioned they are. When compared to a well cut diamond in the face up position (looking straight down at it), a shallow cut will look larger and a deep cut diamond will look smaller.
To begin with please understand that there is no systematic increase in cost as the quality of each of the 4 Cs gets higher. Here are two separate examples with only one change in the 4 Cs:
Example 1 (cut, clarity & carat weight remain the same - only color changes) : a one carat round brilliant cut G color VS2 clarity may sell for $700 higher than a one carat H color VS2 clarity.
Example 2 (cut, color & carat weight remain the same - only clarity changes): a one carat round brilliant cut H color SI1 clarity may sell for $1,045 higher than a one carat H color SI2 clarity.
Change the shape of the diamond and keep everything else the same and the price difference will change again. Supply and demand is a key factor and that is always changing.
