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The 4 C's of Diamonds


In the 1950s, a standard was developed to help jewelers and gemologists measure the quality of diamonds. This universal standard, created by the Gemological Institute of America became known as the four C’s because of the four characteristics by which the gems are measured. They are cut, color, clarity, and carat weight.

This is the established system by which diamonds can be evaluated. The first two C’s, color and clarity, are known as “rarity factors” because these are determined by their natural formation. A high color and clarity grade means the diamond is rarer and therefore more valuable. Clarity and carat weight, on the other hand, are determined by the diamond cutter. Each of these four characteristics are important factors to consider when choosing a diamond.
A modern-style engagement ring sits in a green ring box on a dinner table.

The 4 Cs of Diamonds

Diamond grading is an essential process that plays a crucial role in the value and quality of a diamond. Accurately assessing a diamond's cut, color, clarity, and carat weight requires strict guidelines and precise measurements. The 4 Cs are the essential criteria for grading diamonds; without them, it would be challenging to objectively evaluate a diamond's quality. Diamond grading helps consumers confidently invest in high-quality gems that meet their expectations, providing both assurance and value. With accurate grading, consumers can be confident that they are making informed purchasing decisions based on reliable information about a diamond's true value and quality. For over 30 years, The Wedding Ring Shop’s expert gemologists have worked directly with the world's most trusted and ethical partners to hand-select diamonds for their customers. Only the most beautiful earn their name and the right to be called Hawaii's Most Beautiful Diamonds.

A solitaire engagement ring and a diamond wedding band hang from a twisted chain necklace.


Carat weight is a critical factor in determining the value of a diamond. It is often one of the first things people consider when purchasing a diamond, but it should be noted that carat weight alone does not determine the stone’s value. A diamond's quality and rarity can vary widely even if they have the same carat weight. This is because the other Cs of grading - clarity, color, and cut - all play a role in determining the overall quality of a diamond. For example, a smaller diamond with excellent clarity, color, and cut may be more valuable than a larger stone with lower quality in these areas. Carat weight is still crucial in determining a diamond's value and beauty, and larger gems are generally more valuable than smaller ones.

three yellow gold engagement rings sit on top of each other on a black background.


Diamond cuts refer to how a diamond is cut and shaped, and it plays an important role in a gem's overall beauty and brilliance. GIA (Gemological Institute of America) grades diamond cuts based on the gem’s proportion and symmetry, assigning a cut grade to determine the overall quality. These guidelines are based on the ability of the diamond to reflect and refract light precisely, giving it a stunning and radiant appearance. Here are a few of the many cuts available.


The round cut is the most popular cut by far, accounting for over 75% of all diamonds sold worldwide. This cut features a circular shape and multiple facets, carefully arranged to maximize the gem’s brilliance and fire. The round cut diamond is highly sought after for its classic and timeless look, making it a popular choice for engagement rings and other special occasions.


The princess cut is a square-shaped diamond with sharp corners and a brilliant cut that gives it exceptional sparkle and fire. It is a relatively new cut, first created in the 1980s, and quickly gained popularity for its unique and contemporary style. Princess cut diamonds are often used in engagement rings and are highly prized for their stunning beauty and modern aesthetic.

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The emerald cut diamond is rectangular with long facets and a "hall of mirrors" effect, where light reflects off the gem’s numerous planes and resembles an infinite hallway. It gives it a marvelous appearance. This cut is often used in high-end jewelry and is highly sought after for its unique and elegant look. Emerald cut diamonds are typically larger in size, making them a popular choice for engagement rings and other statement jewelry pieces. Their rarity gives them an exclusive chic.


The cushion cut diamond is square with rounded corners and large facets, giving it a warm and vintage look. Some say it resembles a pillow, hence the title. This cut was popular in the 19th and early 20th centuries. It has recently regained popularity for its unique and romantic style.


The pear cut diamond is a teardrop-shaped diamond with a rounded bottom and a pointed top, giving it a sharp and distinctive look. This cut is highly versatile and can be used in various jewelry pieces, from engagement rings to earrings and pendants. The pear cut diamond is celebrated for its allure and grace. It is often used in combination with other diamond cuts to create stunning and unique jewelry pieces.

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The Gemological Institute of America (GIA) has a standardized grading system for diamond clarity. They use a 6-point scale ranging from Flawless (FL) to Included (I). Within this scale are several subcategories based on the number, size, and location of inclusions and blemishes. The categories are as follows: Flawless (FL), Internally Flawless (IF), Very, Very Slightly Included (VVS1 and VVS2), Very Slightly Included (VS1 and VS2), Slightly Included (SI1 and SI2), and Included (I1, I2, and I3). The higher the grade, the fewer and less noticeable the inclusions or blemishes, and the more valuable the diamond. The clarity grade is determined by examining the diamond under 10x magnification and assessing any inclusions or blemishes' presence, size, and location.


Inclusions are internal characteristics or imperfections within a diamond, such as small cracks, air bubbles, or mineral deposits. They can affect the diamond's overall clarity grade and lower its value. Inclusions can also impact a diamond's durability, as they can weaken the structure of the diamond and make it more prone to damage or breakage.


Blemishes are external characteristics or imperfections on the surface of a diamond, such as scratches, pits, or nicks. They can also lower the diamond's clarity grade and reduce its value. Unlike inclusions, blemishes do not usually affect the diamond's durability or strength but can impact its overall appearance and shine. It is important to note that many blemishes can be removed through polishing or other treatments, while inclusions are generally permanent.

A woman with a halo princess cut engagement ring touches a man’s arm.


Diamond color is an essential quality to consider when purchasing a diamond. The GIA diamond color scale ranges from D to Z, with D completely colorless and Z having a yellow or brown tint. Diamonds with a higher color grade are more valuable and sought after because they appear whiter and brighter. However, some colorful diamonds can be more valuable than colorless diamonds. These fancy-colored diamonds come in various hues, including pink, blue, green, red, and yellow. The color of a diamond can also be affected by fluorescence, which can make a diamond appear more yellow or blue under certain lighting conditions.

a pear-shaped diamond engagement ring sits between two wedding bands on a white surface.

Browse Brilliant Diamonds at The Wedding Ring Shop

The Wedding Ring Shop is Hawaii's premier diamond jewelry retailer, renowned for our exquisite selection of high-quality diamonds. With over 70 years of experience in the industry, we have a deep understanding of what makes a diamond truly special. Our store's team of expert jewelers is committed to providing their customers with the finest quality diamonds, ensuring that each and every piece of jewelry is an exceptional work of art. Whether looking for an engagement ring, wedding band, or any other diamond jewelry, we are the perfect destination to find Hawaii's Most Beautiful Diamonds. Call our Honolulu showroom at (808) 945-7766 to speak with us today.