The 4Cs of Diamonds
Searching for a sparkling diamond? Selecting a diamond starts by understanding the unique characteristics of each stone. Diamonds are graded based off the 4Cs - cut, colour, clarity and carat weight. The 4Cs of diamonds impact the stone’s beauty and value. Learn more about each of the diamond 4Cs below.
Cut measures how well-proportioned a diamond’s dimensions are including the balance and brilliance of its facets. Diamond cut is considered the most important of the four Cs.
Learn More About Cut
Diamond colour refers to how colourless a diamond is. Colour is the second most important of the 4Cs of diamonds. The less colour, the higher the grade.
Learn More About Colour
Clarity assesses small imperfections within a diamond. Inclusions can occur naturally during the diamond forming process. Clarity is used to quantify and specify any inclusions.
Learn More About Clarity
Carat measures a diamond’s weight. An objective measurement, carat weight is the most popular indicator for showing how large a diamond is.
Learn More About Carat
Though not one of the 4Cs, shape is still an important factor to consider when buying a diamond. Each shape has different attributes that can affect price and quality grades.
Learn More About Shape
Putting it All Together with Diamond Quality
As the largest online diamond retailer, we offer a vast collection of the world’s finest cut diamonds. Our diamonds are pre-selected for exceptional quality with well-graded elements of the 4Cs: cut, colour, and clarity.
Each of the individual 4Cs of diamonds may interact with one another to impact a stone’s overall appearance. For example, an ideal cut diamond may appear less brilliant if its colour rating is L or M. A well-cut stone may appear larger than a diamond of the same carat weight thanks to increased light reflection.
The 4Cs of our loose diamonds are evaluated based on a standardized grading scale. Each loose diamond is accompanied by a grading report from either GIA, AGSL or GemEx, independent diamond grading labs with stringent grading and certification guidelines to analyse diamond quality.
Fancy Shapes and the Four Cs of Diamonds
While round brilliant is the most popular diamond shape, there are many other shapes available. We offer nine different fancy-shaped diamonds that bring a personality all their own. Also known as fancy-cut stones, these diamonds are still graded by their cut, colour, clarity and carat weight.
The 4Cs of diamonds can behave a little differently for fancy cuts. Cs such as clarity and carat can be more forgiving in fancy-shape diamonds. Larger tables can make these diamonds appear larger, maximizing a lower carat weight. Inclusions that are a consideration for round diamonds may be disguised or removed altogether in more specialized cuts. Fancy-shaped diamond 4Cs are also unique in terms of clarity, with different shaped stones adding their own faceting to the mix.
While diamond colour is one of the four Cs in respect to how colourless a stone is, there are some diamonds where colourful hues are intentional and even prized. Coloured diamonds are available in hues of yellow, pink, green, blue and even brown. For fancy colour diamonds, colour isn't about how colourless the diamond is, instead it’s about the stone’s hue, intensity, overtones and saturation. When shopping for coloured diamonds, the Cs of cut, clarity and carat weight are also still important.
How to Buy a Diamond
With so many diamonds for sale, there are a lot of options to choose from. Buying a diamond doesn't have to feel like a guessing game. Learning a little about the 4Cs, diamond quality and how these influence diamond price can make the buying journey a simple one.
Every purchase is unique, but there are some core steps for buying a diamond that you can expect to navigate as you find the perfect fit.
Diamond Buying Guide FAQs
|Grade||Not Carried by Blue Nile||Blue Nile Quality|
|Cut||Fair and Poor||Good, Very Good, Ideal, and Astor Ideal|
|Colour||L, M, N, O, P, Q, R, S, T, U, V, W, X, Y, and Z||K, J, I, H, G, F, E, and D|
|Clarity||I1, I2, and I3||SI2, SI1, VS2, VS1, VVS2, VVS1, IF, and FL|
Price Match Guarantee
If you find a comparable GIA-graded diamond at a lower price, we'll review to match the price.
Diamond Upgrade Program
We offer a lifetime diamond upgrade program on all GIA and AGSL-graded diamonds.