Valentine’s Day Sale | Save Up to 50%
› DETAILS

How to Buy Diamonds: 4Cs, Shopping Tips & More


The 4Cs Of Diamonds


Buying a diamond starts by understanding the unique characteristics of each stone. After all, no two diamonds are the same. To help you make sense of shopping for these timeless gems, diamonds are graded based off the 4Cs - cut, color, clarity, and carat weight. The 4Cs of diamonds impact a stone’s beauty and value. Keep reading to learn more about each of the diamond 4Cs, what these elements mean for diamond appearance and price, plus tips for finding the perfect diamond.
  


Diamond Cut

Cut

 
Cut measures how well-proportioned a diamond’s dimensions are, including its balance and brilliance. This influences how well a diamond interacts with light, impacting its brilliance, fire and scintillation. A well-cut diamond will look its very best with optimal light performance. Diamond cut is considered the most important of the four Cs. No matter which diamond jewelry style you choose, you’ll always want to prioritize cut.  
Diamond Color

Color

 
Diamond color refers to how colorless a diamond is. Color is the second most important of the 4Cs of diamonds. Colorlessness is a desirable feature in most diamonds and the more colorless diamonds are rarer. The less color a diamond has, the higher the diamond color grade. Certain jewelry metals can complement faint color diamonds, so diamond color is a flexible 4C that can vary depending on preferences and jewelry settings.  

Diamond Clarity

Clarity

 
Clarity assesses small imperfections within a diamond. Inclusions can occur naturally during the diamond forming process for both natural and lab diamonds. Clarity is used to quantify and specify any inclusions. When it comes to the four Cs of diamonds, clarity is typically not the most important, as many blemishes are too small to be seen without magnification. But some larger blemishes can be visible. Review a diamond’s clarity plot to see its inclusions.  

Diamond Carat

Carat Weight

 
Carat measures a diamond’s weight, not its size. This 4C of diamonds dates back to the 1500s when carob seeds were used to measure diamonds and gemstones. Today, carat refers to an exact weight of 200 milligrams. Carat weight choice is a matter of preference, one weight is not necessarily better than another. Typically, heavier high-quality diamonds are rarer than ones with lower carat weights and diamond prices can reflect this.
  
Diamond Shape

Shape

 
Shape refers to the outline or overall physical form of a diamond. Though it’s not one of the 4Cs of diamonds, shape is still an important factor to consider when buying a diamond. Each shape has different attributes that can affect price and quality grades. Some shapes may look larger for their carat weights, and others may hide blemishes well.  

Diamond Certification

Certification

 
Diamond reports and certifications can provide the full information on a diamond’s cut, color, clarity and carat weight. Unbiased diamond grading reports are offered with every Blue Nile diamond. 

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, color, carat, 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 color 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. Because of this, it’s possible to focus on just a few of the four Cs of diamonds that matter most to you and still enjoy a stunning gem.
 
The 4Cs of our loose diamonds are evaluated based on a standardized grading scale. Each certified diamond is accompanied by a grading report from either GIA, AGSL, IGI, or GemEx. These are trusted independent diamond assessment labs with stringent grading and certification guidelines to accurately analyze the 4Cs of diamonds.  

Within each of the 4Cs, there are various grading levels and qualities to consider for a given diamond. Review our summary diamond 4C chart below to understand the quality grades for each of the four Cs of diamonds.
  
Chart displaying the Cut, Color, and Clarity grades carried by Blue Nile compared to low quality grades not carried by Blue Nile.

Fancy Shapes And The Four Cs Of Diamonds

 
Most diamond education surrounding the 4Cs focuses on standard diamond shapes, but there are also other fancy shapes which still require assessment. 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, color, clarity, and carat weight.
  
The 4Cs of diamonds can behave a little differently for fancy cuts. Elements such as clarity and carat can be more forgiving in fancy-shape diamonds. Larger tables can make these diamonds appear bigger, 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.

Even if you’re buying a fancy-shaped stone, it’s still important to consider the four Cs of diamonds and how they influence your gem’s value and appearance.  
 

Colorful Diamonds and the 4Cs

 
While diamond color is one of the four Cs in respect to how colorless a stone is, there are some diamonds where colorful hues are intentional and even prized. Colored diamonds are available in hues of yellow, pink, green, blue and even brown. For fancy color diamonds, color isn't about how colorless the diamond is, instead it’s about the stone’s hue, intensity, overtones, and saturation. 

Diamond guide tips for these colorful diamonds are a little different as more intense colors are often prized in these gems. When shopping for colored 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.

There are three main steps to buying the perfect diamond. First, you should familiarize yourself with the 4Cs of diamonds to understand how these factors influence diamond price and beauty. Then, you should begin browsing selections from diamond sellers you trust to see what these gems look like. You can compare diamonds side by side to get a better idea of how they differ. Finally, you can pick the diamond that best matches your budget and the wearer’s tastes. 

If you have any questions on how to buy a diamond or need help assessing which diamond qualities are most important to your purchase, we encourage you to reach out to our experts at our local jewelry stores or through a personalized online jewelry shopping experience. Our diamond experts are always happy to help you learn more about the 4Cs, contact us for help with any questions you may have.  

Further Diamond Education Reading


Looking for more diamond guides, buying tips or details about the 4Cs? Explore more of our diamond education pages:




Diamond Buying Guide FAQs

Explore our diamond education and diamond buying guide FAQs for answers to the biggest questions about the 4Cs of diamonds and how they influence the price, beauty and brilliance of diamonds. You can also review our diamond guides for each of the 4Cs for more information about their qualities and considerations.

What grade of diamond is best?

The best diamond grade is the one that matches your budget. Each of the 4Cs has its own grades and our Astor diamonds represent the highest-graded stones available in all of the four Cs. These diamonds feature unparalleled brilliance, beauty and light performance.  

Which of the 4Cs of diamonds is most important?

Cut is the most important characteristic of the 4Cs. Cut is responsible for the diamond’s brilliance. A symmetrical, proportionate diamond cut will bring the most sparkle.

If you’re wondering which of the four Cs to focus on, cut should be your biggest priority.  

Which of the diamond 4Cs is least important?

Clarity is believed to be the least important of the four Cs. This is because many imperfections are difficult to see without magnification.

How do the 4Cs impact a diamond’s price?

The higher quality a diamond is, the more expensive it will be. Each stone is unique and many less-than-perfect grades in some of the 4Cs are difficult to see with the unaided eye. For example, stones with a lower clarity score may still look eye-clean. Because of the uniqueness of diamonds, it’s possible to choose a stone with lower scoring elements of the 4Cs and still enjoy a breathtakingly beautiful diamond.

What are tips for buying diamonds?

The process for how to buy diamonds doesn’t have to be complicated. Today, there are in-depth diamond guides, detailed online photos of diamonds and experts on hand to help answer any questions you may have. The easiest way to buy a diamond is to browse our selections online and review the diamond grading reports of your favorite gems to make sense of their 4Cs. Our experts are always available to help with any questions you have about how to buy a diamond or understand its grading report.

What do the 4Cs mean for diamonds?

The four Cs of diamonds, often called the 4Cs, are standardized diamond grading parameters that make it easy to understand a diamond’s features. The 4Cs are color, cut, clarity, and carat. The standardization of the 4Cs of diamonds makes it easy to compare and contrast different diamonds as you browse.

Is there a 5th C of diamonds?

Many people consider diamond certification to be the unofficial 5th C. Diamond guides and grading facilities are not all equal, and it’s important to choose diamonds that have been graded by reputable institutions such as GIA, AGSL, IGI, and GemEx.

Can lab diamonds be graded for the 4Cs?

Yes, diamond 4C charts and grades are available for high-quality lab diamonds. We offer stunning natural and lab diamonds that are assessed for their 4Cs.