The 4 C's of Diamonds

The purchase of a diamond can be a challenge. For this reason, we have prepared a guide to help you find the diamond that is right for you. Read on to learn about the four characteristics or 4C's which describe a diamond and ultimately determine its value.


Carat is the unique measure of weight for diamonds and gemstones. One carat is equal to 200 milligrams or 0.2 grams.

“Total Carat Weight” is a phrase used to describe the total weight of all of the diamonds or gemstones in a piece of jewelry, including the center gemstone.


Although a diamond may appear white or colorless to the naked eye, truly colorless diamonds are very rare. The less color a diamond has, the higher the rarity and value. Diamond color is graded along a spectrum, with D being colorless, and Z having a light yellow hue. Color is determined by comparing a diamond to a master set, and the grading is a measure of how noticable a color is.

Color Scale

Sample Color Diagram


Clarity refers to the imperfections of a diamond, including carbon pinpoints, feathery crystals, and other natural formations. These characteristics are created during a diamonds formation, and help gemologists identify individual stones. Clarity is graded on a scale from F (flawless) to I-3 (heavily included).

Clarity Scale

Sample Clarity Diagrams


Cut sometimes refers to the overall shape of a diamond, but is most often used to describe a diamonds quality of cut and finish. The 4th C determines how well your diamond interacts with light. It is through a unique combination of well-balanced proportions, and the highest craftsmanship that maximizes your diamonds brightness, scintillation and fire.

Cut grading is based on several different components with the main focus being Polish, Symmetry and Cut. These three factors, along with expert craftsmanship from an experienced diamond cutter, unlock a diamonds Brightness: the overall brightness of a diamond, Scintillation: the white flashes or white colored sparkles, and Fire: flashes of spectral colors such as red, blue, green, etc. The better the craftsmanship, the better the sparkle!

Cut Scale



Shape refers to the outlining appearance of a gemstone. Cut and Shape are sometimes used interchangeably.


Polish describes the finish and clarity of a diamond. A poorly polished diamond will have polish lines, and a rougher texture that may effect sparkle.

Polish Scale

A grade of Good and above will have the least effect on the brilliance of the diamond.


The Symmetry grade refers to the alignment of diamond facets. Each round diamond has 58 facets that must be proportionately sized and aligned. Without proper symmetry, the light entering a diamond is misdirected as it enters and exits the diamond, resulting in a difference in sparkle.

Symmetry Scale

A grade of Good and above will have the least effect on the brilliance of the diamond.


Fluorescence is the visible light some diamonds emit when exposed to ultraviolet light. Blue is the most common color of fluorescence, but other colors such as yellow may be visible. Fluorescence is a naturally occurring visual phenomenon that happens, and although not all diamonds demonstrate this property, it can be used to help in identification. Fluorescence comes in varying degrees from none, faint, medium, strong, and very strong.

Fluorescence Scale

The prescence of strong fluorescence may affect the diamond by showing a milky or cloudy appearance. Though not all diamonds are affected, it is always best to view fluorescent diamonds in direct sunlight, compared to a non fluorescent diamond, to make sure your diamond isn’t affected before purchasing.


At Giraux a majority of our gemstones are graded by laboratories such as G.I.A and E.G.L. These gemstones come with a comprehensive report that assesses each of the 4 C’s. Many diamonds also come with a laser insciption that matches an individual gemstone with its certificate.

A certification from G.I.A has the strictest standards, and uses the International Diamond Grading System. A report from G.I.A will include your diamonds grading, measurements, a map of inclusions, a diagram of diamond proportions, and more. Always make sure you compare apples to apples.