The weight of a diamond is expressed in carats (ct.), not to be confused with carat content of gold. 1 carat = 0.20 grams. The weight determines the size of the diamond. A round diamond of 1 ct. has a diameter of about 6.5 mm. Weight is the characteristic that has by far the most influence on price. The larger a diamond, the larger also the price per carat. Because of this, the value of a diamond also increases almost exponentially as its weight increases. Along with the cut, carat weight is the diamond's most visible characteristic.

Most diamonds have a slight yellow hue. The degree to which a diamond contains color is shown on a scale from D to Z. D is the best grade and is completely colorless. D, E and F are the top colors. These contain virtually no other color. Viewed along the top, these will always look lighter and whiter than other colors. G and H are commercial colors. These are not yellowish in color, but are darker than D, E & F. Diamonds of I contain a visible yellowish tint.
A difference in color gradation is relatively visible. Therefore, we always advise our customers to always prioritize color over clarity when choosing a diamond.

The purity of a diamond is examined with a loupe at x10 magnification. This goes from Loupe Clean: no impurities visible to VVS: very very small impurities visible with the loupe, invisible to the naked eye, VS: Very small inclusion, invisible to the naked eye, to SI: Small inclusion, possibly visible to the naked eye to I: clearly visible impurity.

At Van der Veken, we always select diamonds that are completely pure to the naked eye.

The brilliance of the diamond depends largely on the way it is cut (Cut). A small deviation can cause the diamond to "leak" light, making a shadow visible in the stone.

The quality of the cut is the most difficult of the 4 c's to assess. This is why most laboratories go no further than distinguishing between poor, fair, good, very good or excellent.

In addition to the quality of the cut itself, the shape also plays a role, of course. Most shapes are designed to reflect a maximum amount of light, giving the diamond the greatest possible brilliance. The round Brilliant is probably the best known cut. Other common shapes are "Marquise," "Emerald" and "Princess.