A lot of love goes into creating a beautiful diamond. The world of diamonds is expansive, and the amount of information available can seem overwhelming for many diamond buyers. 

Diamonds are among the most popular of the precious stones, and many carry sentimental value for the wearer. Diamonds can be the centerpiece of engagement rings, portable memorials, family heirlooms, and other meaningful items throughout our lives.

When we go shopping for a diamond, we want to know that we’re getting the best value for our money. That means we’ll want to know not only the style that we want but also how to determine the value of the stones we’re considering. 

While there are plenty of professionals willing to help you along the way, having some basic knowledge of what makes a diamond valuable will greatly help you make sure that you are purchasing the perfect stone that is just right for you. 

One of the tools that can help you understand diamond quality is known as a clarity chart. To better understand how a clarity chart works, you need to know the 4cs of the diamond grading system and how a diamond is formed. 

How Are Diamonds Made?

Diamonds are famous for being pure, sparkling, and transparent gemstones that catch the light like nothing else on Earth. Not only that, but diamonds are the hardest naturally-forming substance on the planet and surprisingly light considering their unique toughness. 

So, how does this incredible stone get formed, and where do diamonds come from? Knowing the basics of diamond creation will help you better understand their grading scale and clarity chart.

In the Deep 

About 100 miles beneath the surface, diamonds are formed in the Earth’s mantle. This incredible depth allows two very specific conditions to be met that are necessary to form diamonds: intense heat and extreme pressure. 

The temperature in the Earth's mantle where a diamond is naturally formed can reach upwards of 2000 degrees Fahrenheit, and the pressure can reach an astounding 725,000 PSI (pounds per square inch). These are extreme conditions that are perfect for transforming pure carbon into a diamond. 

Within these conditions, carbon atoms can meld together in a specific tetrahedral shape and form an infinite layer of carbon. This very specific arrangement of carbon produces the clear, glass-like stone we know as a diamond. 

Next, these stones have to make their 100-mile journey up to the surface. Most diamonds find their way to the surface thanks to volcanoes. A volcanic disturbance will rip up pieces of the earth’s mantle and transport them to the surface, where they can be mined.  

Diamond Grading Scale: The 4 Cs

With such an intense formation process, it makes sense that not all diamonds are the same. Each diamond is unique and has certain properties that affect its value. In the world of precious stones, the general rule of thumb is that the rarer a jewel, the more valuable it is. 

When it comes to diamonds, the rarest jewels are the most translucent ones with the smallest number of imperfections. These characteristics make pure, clear diamonds extremely valuable. 

The four Cs of diamond grading is a system that assesses a diamond’s natural properties to determine its worth. The four categories (Cs) of the grading system are color, cut, carat, and clarity. 


The purer a diamond is, the less color it will have. This is due to a diamond’s molecular structure. Remember, a diamond is made entirely of carbon atoms. This means that during its formation, the carbon atoms themselves need to take on very specific shapes and bond with each other. 

Diamonds are not the only substances that are composed of pure carbon. The carbon needs to be arranged in a certain way to create a diamond. Otherwise, substances like graphite may form instead. When an element like pure carbon can create multiple substances, these substances are called allotropes. 

When a diamond is forming, the more perfect the atomic structure of the stone, the more colorless it will be. A completely colorless diamond is considered the rarest and most valuable. However, some buyers specifically look for artificially colored diamonds, and naturally colored diamonds like the Hope diamond can be even more valuable than their transparent counterparts.


A diamond’s cut depends on an artisan’s skill more than the diamond’s natural formation. Diamonds can capture and reflect light in stunning ways, and this characteristic is called the sparkle and brilliance of a diamond. 

Every diamond has a unique pattern and physical quality of shimmer and sparkle. This means that each diamond has a specific cut that best fits that diamond to bring out the most brilliance and sparkle possible. These cuts can also hide inclusions or remove minor inclusions naturally present in the stone.

Certain step cuts, like Asscher or emerald cut diamonds, make visible inclusions more apparent. However, trained gemologists are able to cut these minerals in a way that enhances their natural brilliance, rather than exacerbating flaws. 

A master diamond cutter is a person who is trained to understand a diamond’s natural potential to brilliance and sparkle and cut the diamond to achieve it. Popular diamond cuts include pear, princess, cushion, and marquise. 


Carat refers to the weight of a diamond and is a unit of measurement exclusively used for precious stones. A carat’s actual weight is 0.200 grams. Typically, heavier diamonds are more expensive to purchase. Of course, other factors like a diamond’s age, history, and setting can similarly affect its price.


A diamond's clarity grade refers to the absence of inclusions and blemishes. These are natural imperfections in a diamond that hinder the passage of light and often cannot be seen with the unaided eye. A blemish is when one of these imperfections is on the outer surface of a diamond, and inclusion is when the imperfection is internal. 

Clarity Chart and How To Understand It

Every one of the four Cs has a specific grading chart associated with it. The clarity chart is composed of six categories and eleven total clarity grades. Although these imperfections can be rather small and unnoticeable to the naked eye, trained graders make use of special tools to determine a diamond’s clarity grade. 

The six categories are:

  • Flawless (FL)
  • Internally Flawless
  • Very, Very Slightly Included (VVS)
  • Very Slightly Included (VS)
  • Slightly Included (SI)
  • Included 

The chart runs from included—which are flaws a skilled grader can see under 10x magnification that affects the way the diamond interacts with light—all the way to flawless. There are eleven grades altogether, and each one refers to a different level of imperfection.


These diamonds can have a grading of I1, I2, or I3. These are the most included and the lowest grades.

Slightly Included

The next category has only two grades, SI1, and SI2. The inclusions on this level are noticeable under the magnification of 10x but are not as obvious to the naked eye as included diamonds.

Very Slightly Included 

This category also has two gradings of VS1 and VS2. These inclusions are not quite as obvious even under magnification. 

Very Very Slightly Included

As the name implies, this grade is awarded to the diamonds with the least amount of inclusion present without being flawless. These inclusions are given the grades of VVS1 and VVS2. These inclusions are typically hard to find, and it takes the best grading experts to discover these diamonds’ flaws.

Internally Flawless  

This grade is awarded to a flawless diamond that has no internal inclusions up to 10x magnification. However, they may still have blemishes.


The FL grade is given to a flawless diamond. As the name implies, this diamond has no blemishes or inclusions visible under the standard of 10x magnification. This is the rarest grade that a diamond can have on the clarity chart, so flawless diamonds are typically the most expensive. 

The Diamond Grading Chart

Whether you are interested in buying a diamond or are simply curious to know more about these precious and sentimental stones, this knowledge can help you better understand what a diamond grading chart is and how to use it. 


Finding and Making Diamonds | Ask An Earth and Space Scientist

Clarity Chart | GIA

4Cs of Diamond Quality | GIA