The 4 Cs of Diamonds

Various characteristics of diamonds are graded and categorised by the diamond industry. To learn about diamonds is to first learn about the “four Cs” of diamonds — the four characteristics which are considered the most important in determining a diamond’s value

cut

Cut is probably the most important, and most challenging, of the four Cs to understand.

Clarity

Most diamonds contain some inner flaws, or inclusions, that occur during the formation process.

Colour

Colorless diamonds are the most desirable since they allow the most refraction of light (sparkle).

Carat weight

A carat is the unit of weight by which a diamond is measured.

How to choose a Diamond?

We select our diamonds using a universal standard certified by the G.I.A (Gemological Institute of America). Please turn the volume on and watch this educational video provided by G.I.A. 

Watch to learn more

This video will explain everything you need to know about the four main characteristics of a diamond, and what to look for when shopping around.

This video has been uploaded by GIA on YouTube.

Diamond Colour

The colour evaluation of most quality diamonds is based on the absence of colour. A pure and structurally perfect diamond has no hue, like a drop of pure water and consequently, a higher value. At One Carat Diamonds we use the G.I.A. D – Z colour – grading system which measures the degree of colourlessness in a diamond. ​

​Each diamond offered to our clients is compared under controlled lighting and precise viewing conditions to master stones of established colour value. One Carat Diamonds specialise in white diamonds which exhibit grades from D – G and fancy coloured diamonds ranging in all colours.

This video has been uploaded by GIA on YouTube.

Diamond Clarity

Natural diamonds are the result of carbon exposed to tremendous heat and pressure deep in the earth. This process can result in a variety of internal characteristics called “inclusions” and external characteristics called “blemishes”. ​The evaluation of diamond clarity involves determining the number, size, relief, nature, and position of these characteristics, as well as, how these affect the overall appearance of the stone.

​While no diamond is perfectly pure, the closer it comes, the higher it’s value. At One Carat all our diamonds are hand sorted twice and are only selected if the diamond is eye clean by nature and includes (if any) inclusions will not affect the diamond in its life. We specialise in clarity grades from Flawless to SI on the G.I.A scale.

This video has been uploaded by GIA on YouTube.

Diamond Cut

Diamonds are renowned for their ability to transmit light and scintillate so intensely. We often think of a diamond’s cut as a shape (round, emerald, pear etc), but a diamond’s cut grade is really about how well a diamond’s facets interact with light.

​One Carat Diamonds only hand select diamonds that adhere to precision artistry and workmanship that is required to fashion a stone so its proportions, symmetry and polish deliver the magnificent return of light only possible in a diamond. We recommend only diamonds cut with an “Excellent” or “Very Good” cut grade.​

This video has been uploaded by GIA on YouTube.

Diamond Carat Weight

The size of a diamond is expressed in terms of its weight in carats and points; 100 points = 1.00 carat. The carat weight refers to the diamond weight and is a rough reflection of the overall size of the diamond (but not the quality of the diamond). A diamond’s value increases exponentially with size, meaning that 1.00ct diamond will typically cost more than twice the price of a 0.50ct stone of similar quality.

Prices also tend to step up at the most popular weights such as 0.50cts, 0.70cts and 1.00ct, so often you achieve better value if you can find a diamond that you like just below one of these levels. ​For example, instead of 1.00 carat diamond (6.4mm), consider a 0.90cts (6.2mm). The difference in size will be negligible but, savings here can be significant.​

This video has been uploaded by GIA on YouTube.

Our Diamonds

We select our diamonds using a universal standard certified by the G.I.A (Gemological Institute of America). This ensures that One Carat Diamonds sets its creations with the highest-quality diamonds, by being extremely selective through the G.I.A criteria known as the 4C’s; Cut, Colour, Clarity & Carat Weight.


Every diamond of more than 0.30 carats comes with a G.I.A certificate and individual certificate number engraved on the stone. Invisible to the naked eye, this engraving guarantees the authenticity and uniqueness of our diamonds. The G.I.A diamond certificate is considered the benchmark to which all others are compared.


In addition to the 4C’s, the final criterion is of One Carat Diamonds own, the nobility of the stone. Our experts select each diamond using light, magnifying glass and microscope for the specific emotion it arouses, its brilliance, its fire and its sparkle.

Analysis and Grading

GIA reports represent the highest standard of reliability, consistency and integrity. And now, GIA Report Check is available for all GIA reports, providing you with an additional level of assurance. With Report Check, you can quickly and conveniently confirm that the information on your report matches what is archived in the GIA report database.

Want to look up a report?

Book a consultation today?

Analysis and Grading

GIA reports represent the highest standard of reliability, consistency and integrity. And now, GIA Report Check is available for all GIA reports, providing you with an additional level of assurance. With Report Check, you can quickly and conveniently confirm that the information on your report matches what is archived in the GIA report database.

Want to look up a report?

Book a consultation today?