What are the 4 C’s of a diamond?

When choosing an investment diamond, some basic knowledge of diamonds is crucial. The value of a diamond is determined by the 4 C’s, being carat, colour, clarity and cut. The score on these properties determine the quality of the diamond.

The 4 C’s specify the quality of a diamond and are used to identify gemstones.


The weight and size of a stone is expressed in carat.


The colour gradation of a colourless diamond ranges from D (colourless) to Z (yellowish).


Most diamonds have impurities, called inclusions.


The cut refers to the proportions, symmetry and shine of a diamond.



The carat of a diamond is determined by the weight of the diamond. The bigger the diamond, the higher the carat weight. One carat is equal to 200 milligrams. The carat of a diamond will determine the value and price of the gemstone.

The price of a diamond rises exponentially as the carat weight increases. The value of a diamond of 2.00 carat is more likely triple the price (and not double) of a 1.00 carat diamond with similar characteristics.

Especially the symbolic value of carat for diamonds cannot be overstated. For example, the difference between a 0.98 ct. diamond and one of 1.01 ct. can hardly be seen, but their prices might be much further apart than you would expect. The difference in price can be explained by the fact that we cross a ‘magic size’. Magic sizes are, for example, 1 carat, 1.50 carat or 2 carats. Once we reach that magic size, the price increases exponentially.

We recommend diamonds ranging from 1 ct to 5 carat


An international colour gradation system provides a code from D to Z, where D is fully colourless and Z is a yellow hue. A diamond with colour D is the most valuable. The colour of colourless investment diamonds standard varies between D and G.

There are also coloured diamonds, in brown, orange, pink, red, yellow, green or blue. Depending on their colour, they are incredibly rare, which also determines their monetary value. In general, their price is higher than the colourless diamonds due to their rarity. Very intense coloured diamonds are called fancy coloured diamonds. This is always listed on the certificate.

We have noticed that there is only a very small market for especially rare diamonds (very large, coloured and with a fancy cut). Would you like to invest in coloured diamonds? The experts at BAUNAT DIAMONDS are happy to assist you.

We recommend investing in colourless diamonds of D, E, F and G colour


The vast majority of all diamonds have inclusions – impurities on the inside of the diamond. Most inclusions are not visible to the naked eye. The diamond is given a score after experts from an institute like GIA have studied it for impurities under a tenfold magnification through a microscope.

Inclusions can obstruct the sparkle of a diamond. They block the reflection of light if they are in the path of the light.

Of course, impurities should not impeach the beauty of the diamond. To guarantee that, we only select diamonds with inclusions that are not visible to the naked eye.

Two types of inclusions:

The clarity of the diamond can be flawed in two ways:

External impurities occur during the cutting process or are the result of daily use.
Internal impurities regard inclusions inside the gemstone. There are different types.

Most common inclusions:

The most common internal inclusions consist of three subtypes. Black or dark spots inside the diamond are generally forms of coal. Then there are clouds. These are microscopic veils. Lastly, there are ‘feathers’. These are the most prevalent inclusions and are the result of molecular fractions that arose during the thousands of years-long formation process of diamonds.

BAUNAT DIAMONDS recommends clarities of VS1 or higher for investing in diamonds

Cut quality

Perhaps the most important property of a diamond is the quality of the cut. The level of the cut of a diamond determines how bright it shines and twinkels. It is also the only human factor. The cut quality is determined by the proportions, symmetry and the extent to which the diamond shimmers. A well-cut diamond reflects almost all the light back through the crown (where it also enteres) back outside. This gives a diamond its characteristic radiance.

BAUNAT DIAMONDS only works with Very Good and Excellent cut diamonds

Cut shape

In addition to cut quality, ‘cut’ can also refer to the diamond shape. Although this property is not part of the 4 C’s, we still recommend paying attention to it when selecting investment diamonds.

The round brilliant is by far the most requested cut form. The 58 facets allow the light that enters to reach maximum refraction. This gives brilliants their characteristic radiance that is so highly prized in diamond jewellery.

Fancy cut

Other shapes than the standard round brilliant are called fancy cut shapes. The most famous are the pear, the oval, the heart and the emerald. At BAUNAT DIAMONDS, we have a collection of “Special Diamonds” on demand to invest in.

Would you like to learn more about all your investment options? Ask for advice from your diamond expert at BAUNAT DIAMONDS via mail or chat or talk with our team directly at +32 3 201 24 90.

All investments carry risk and all investment decisions of an individual remain the responsibility of that individual.

Our diamonds

With the widest selection of certified diamonds in the world, we offer the 10 classic diamond shapes, from 1.00 ct. and up. All our high-quality diamonds were purchased ethically responsibly and certified by a renowned international diamond certification organisation, such as GIA, IGI and HRD.

Start to invest See our selection of loose diamonds