Diamond Education

The Four Cs

Fine diamonds are among the most desired of all gems, the purchase of which will be one of the most important in your life. A diamonds value, however, differs widely from one stone to another. Experts evaluate every diamond for individual beauty and rarity, using four primary guidelines. These are commonly referred to as The Four Cs -- Cut, Colour, Clarity, and Carat Weight.

Cut

While cut does refer to the shape, it also refers to how the diamond is actually cut. Its overall proportions, as well the size and placement of its many reflective surfaces or facets play a large part in “cut”. The consistency and balance of these can greatly affect how the stone captures light and reflects it back to the eye.

A well-cut diamond will appear brilliant and fiery and can also appear larger than other stones of the same carat weight. It is generally considered that the cut of the diamond is the most important characteristic of a diamond because a poorly cut diamond will appear dark and lifeless regardless of its colour or clarity. Diamonds divide light into a spectrum of colour flashes called “fire”.

In essence, the cut is a series of measurements that determines the diamonds brilliance, dimensions and its finish.

If the cut is too shallow, then light is lost out of the bottom causing the diamond to lose brilliance. If the cut is too deep, the light escapes out the sides of the diamond causing it to appear dark and dull.

Colour

With the exception of some fancy coloured diamonds, the most valuable and desirable diamonds are those with the least colour because of their rarity. The colour of a diamond can greatly affect the value of the diamond.

The colour scale for transparent diamonds runs from D-F (colourless), G-J (near colourless), K-L (faint yellow), to Z (light yellow).

The better the colour grade in a diamond, the more colourful the fire will be.

When diamonds are formed with traces of other minerals, rare and beautiful colours may result. These fancy colours range from blue to brilliant yellow to red, brown, pale green, pink, and violet. Because of their rarity, coloured diamonds are highly desirable and can be quite valuable.

Clarity

Clarity of a diamond measures its flawlessness – that is the existence, or absence, of visible flaws. Tiny surface blemishes or internal inclusions, even those seen under magnification with a jeweller’s loupe or microscope, can alter the brilliance of the diamond and affect its value. A truly flawless diamond is extremely rare and priced accordingly.

FL, IF Diamonds - Flawless - No internal or external flaws
VVS1, VVS2 Diamonds - Very, Very Slightly Included -  Very difficult to see inclusions with 10x magnification
VS1, VS2 Diamonds - Very Slightly Included - Inclusions are not typically visible to the unaided eye
SI1, SI2 Diamonds - Slightly Included - Inclusions are visible under 10x magnification and may be visible with the unaided eye
I1, I2, I3 Diamonds - Included - Inclusions are visible with the unaided eye

Carat Weight

The size of a diamond is measured, not only by its dimensions, but by weight, therefore the carat weight may not reflect a diamonds size. Diamonds of equal weight may appear slightly different in size, depending on their depth and proportions.

The diamond cut should be considered in deciding on the carat weight because when a diamond is cut with the proper dimensions, the maximum amount of light is returned to the top of the diamonds. Therefore, when a diamond is cut well the light reflected out of the top makes the stone appear larger. When the diamond is poorly cut, the weight of the diamond may be in the base of the diamond, making it appear smaller than its carat weight.

One carat, the traditional unit of measure for diamonds, is equal to approximately 0.2 grams. You may also hear the carat weight of a diamond referred to in points. A point is equal to 1/100 of a carat; therefore, a 75-point diamonds equals 0.75 carat.