The 4C’s
The 4Cs of Diamond Quality is the universal method for assessing the quality of any diamond, anywhere in the world. As the creator of the Diamond 4Cs and the International Diamond Grading System™, GIA is trusted by museums, auctions houses, and consumers all over the world to grade nature’s finest treasures.
Diamond Cut
Achieving the best cut for a diamond reflects in the stone’s final beauty and value. And of all the diamond 4Cs, it is the most complex and technically difficult to analyze. To determine the cut grade of the standard round brilliant diamond – the shape that dominates the majority of diamond jewelry – GIA calculates the proportions of those facets that influence the diamond’s face-up appearance. These proportions allow GIA to evaluate what the best cut for a diamond is, by studying how successfully a diamond interacts with light to create desirable visual effects, such as:
- Brightness: Internal and external white light reflected from a diamond
- Fire: The scattering of white light into all the colors of the rainbow
- Scintillation: The amount of sparkle a diamond produces, and the pattern of light and dark areas caused by reflections within the diamond
Diamond Colour
Understanding what diamond color means helps in choosing the right diamond. Interestingly, the diamond color evaluation of most gem-quality diamonds is based on the absence of color. A chemically pure and structurally perfect diamond has no hue, like a drop of pure water, and consequently, a higher value.
Diamond Clarity
To understand diamond clarity, we must first understand how diamonds are created. 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.’
If you are trying to determine what is the best clarity for a diamond, remember that no diamond is perfectly pure. But the closer it comes to purity, the better its clarity.
Diamond Carat Weight
To put it simply, diamond carat weight measures how much a diamond weighs.
All else being equal, diamond price increases with diamond carat weight because larger diamonds are rarer and more desirable. However, two diamonds of equal carat weight can have very different values (and prices) depending on three other factors of the diamond 4Cs: Colour, Clarity, and Cut