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How to Use the 4 C’s to Find the Perfect Diamond for Your Engagement Ring

The most eye-catching part of any engagement ring is undoubtedly the center diamond, so choosing the right one for your ring is imperative. Keep reading for some tips on using the 4 C’s to find the diamond of your dreams.


Buying diamonds can be an intimidating process if it’s your first time. It’s difficult to assess the quality and value of a diamond without understanding how diamonds are graded. To stay within your budget, it’s vital to learn about the factors that affect the price of a diamond. There’s no one-size-fits-all stone for all brides.

A lower priced diamond may be the diamond of your dreams compared with a more expensive one. Every diamond has its own unique standout features that appeal to different tastes. Diamond grading is a relatively recent invention created to help customers understand diamonds, especially the 4 C's of diamonds.

The 4 C’s of Diamonds

Since 1931, the Gemological Institute of America (GIA) has been the ultimate authority on diamonds, gemstones, and pearls. This industry-leading nonprofit institute ensures every diamond is examined to rigorous standards under a high-powered microscope. The diamond’s grade determines its price. When shopping for diamonds, consumers are advised to consider the 4 C's of diamonds: carat weight, cut, color, and clarity.

Carat Weight

The first of the 4 C's of diamonds is carat weight, not to be confused with the karat unit of measurement of the purity of gold. Carat weight refers to the weight of the diamond. One “carat” is 200 milligrams. Diamond carat weight (ctw) is measured to the hundredth decimal place. Many jewelers will refer to the carat weight as points. For example, a 0.25 carat would be referred to as a twenty-five-pointer.

As carat weight increases the price will as well, due to the rarity of larger diamonds. While a one point difference in carat weight won’t seem like much of a visual difference, there will be a considerable increase in price for the higher carat diamond.

Many diamond shoppers have gravitated to certain sizes, specifically 0.5 cwt, .75 cwt, and 1 carat. Two diamonds with the same carat weight can have differences in the rest of the 4 C's of diamonds: cut, color, and clarity that affect the price.


Diamonds are adored for their brilliance and fire. Many consumers believe that cut refers to its shape (e.g. princess, round, pear, marquise), but it actually refers to the quality of the diamond’s facets that reflect light. Handcrafted precision can create stunning symmetrical pieces with a high polish and house-of-mirrors effect.

Grading the quality of cut isn’t as clear-cut as the other 4 C's of diamonds. The quality of cut is determined by its brilliance (white light reflections), fire (flashes of color), and scintillation (light and dark flashes in the diamond). Jewelers often have to decide between cutting a rough stone for the best cut or the highest carat weight. Grades for a diamond’s cut range from Excellent to Poor.

A cut meant to maximize carat weight may leave the diamond too shallow for best light reflection. Other diamonds may be cut to minimize inclusions (natural imperfections within the diamond), but sacrifice on the sparkle factor. It’s important to consider the diamond’s 360-degree cut, not just the top-view of the diamond.


Color grading is an evaluation of a diamond’s absence of color. A 23-grade scale from D to Z ranks diamonds from colorless to gray, yellow, and brown hues. Most people consider the colorless diamonds the best, which is a good reason for its hefty price tag.

The visual difference between a D and an E diamond may not be readily noticeable until you see their price. The lower the grade the more tinting you’ll notice, which may detract from the diamond’s light reflections. Naturally colored diamonds are rare and graded based on their color depth and intensity.


As mentioned above, inclusions are imperfections within the diamond. These are referred to as “birthmarks” created during the diamond formation process when carbon is exposed to intense heat and pressure deep in the earth. A “Flawless” diamond grade would feature no inclusions or external blemishes visible under 10x magnification.

Internally Flawless diamonds don’t have any inclusions. Lower graded diamonds feature inclusions that can affect the brilliance and transparency of a diamond. Keep in mind, most diamonds feature some inclusions and blemishes. Additionally, the diamond shape and size can affect their clarity.

Finding the Perfect Diamond for Your Engagement Ring

Final Tips for Choosing the Perfect Diamond

It’s not enough to consider just one of the 4 C's of diamonds. Every factor contributes to the brilliance, fire, and beauty of the precious stone. Most customers will focus on the cut because it’s the most prominent factor contributing to its aesthetic appeal. If you’re working within a budget, you can choose your ideal cut and sacrifice a bit on color and clarity to save a few dollars. It’s not always about the size of the diamond.

Find the Right Diamond at Costello Jewelry Company

Costello Jewelry Company in Naperville or Glen Ellyn, Illinois is a full-service jewelry company that offer customers diamond buying services, jewelry repair, jewelry engraving, and stunning engagement rings. For a closer look at the diamonds from Costello Jewelry Company, feel free to visit any of the two Costello Jewelry Company locations.

We can help you understand the minute differences between diamond so you can make a more informed purchase, and our staff is always on hand to answer any questions you may have about buying diamonds. Contact us with any questions by calling 866-790-3272, or send your inquiry to


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