When buying or selling a diamond, it is important to understand what the 4 C’s are and the role they play in diamond values. Each of these categories will affect the price of your diamond:
- Carat weight
- Color grade
- Clarity grade
- Cut grade
The weight of a diamond has a direct correlation with its price. Gemologists will consult a pricing sheet and apply the relevant price per carat. For example, for a 0.50 carat diamond whose characteristics are valued at $1,200 per carat, you can expect a price of $600. Of course, this might change once you take into account the other components, but it’s a good starting point.
Carat (ct.) is the unit of measurement used to weigh diamonds; 1 ounce is equal to 141.74 carats. Diamonds are weighed on very sensitive scales as a tiny difference in weight can make a huge difference to the value. When diamonds are sold they are priced within weight brackets. There are specific carat weights where the value will jump quite considerably. For example, if you purchase a 0.90ct it could cost you up to 20% less than 1.00ct but the diameter of the diamond may actually be only a few millimeters smaller.
Within a color grading scale, a diamond can fall anywhere between D-Z: colorless to light yellow/light brown. A D color diamond is the rarest color grade and therefore the most valuable. As a diamond color begins to slowly slide from D to Z, it will begin to lose its value.
While it is not always possible for the untrained eye to see the subtle differences in diamond color, these subtle shifts in tone can have a huge impact on price. Two diamonds identical in cut, carat weight and clarity, but different in color will be significantly different in price.
Fluorescence plays a role in color grade. Fluorescence is a type of light emitted when a diamond comes in contact with ultraviolet light and can improve color in low color grade diamonds. On the other hand, if there is fluorescence in a colorless diamond, it can often make the stone milky, lowering its value.
The clarity grade scale ranges from FL (flawless- no imperfections) to I3 (imperfect- eye visible inclusions). Diamond flaws are divided into groups: internal flaws, called inclusions, and surface irregularities, called blemishes.
Inclusions consist of impurities trapped inside the diamond during its formation. Depending on where the inclusions are located, they might remain within the diamond even after it has been cut and polished, and can severely affect the diamond’s appearance depending on their position within the stone. Blemishes are always found on the diamond’s surface and appear as scratches and nicks, also affecting price.
Diamonds are cut, polished and shaped by skilled and experienced craftsmen. The standard industry cut scale for a diamond ranges from Excellent to Poor. Perfect proportions and symmetry of a cut diamond will allow the diamond to reflect the optimum amount of light and look its very best. Each of the tiny flat geometric shapes that you see on your diamond are called facets, and these catch the light and create the beautiful, eye-catching affect we call sparkle. On the other hand, if these proportions are off, the diamond will leak the light and appear darker.
The term ‘cut’ can also refer to a diamond’s shape. The standard cut is a round brilliant and all other shapes are referred to as fancy shapes. Fancy shapes include but are not limited to: princess, marquise, pear, oval, heart, cushion, radiant and emerald.