In the early 20th century, Robert M. Shipley, a former retail jeweler, undertook the task of professionalizing the American jewelry industry. To that end, he established GIA in 1931 to provide formal gemological training to aspiring jewelers. A way to determine a diamond’s value and quality was desperately needed. Shipley standardized the diamond value terms to color, clarity, cut and carat weight nicknaming them the 4Cs This united the world diamond industries on the grading, trade, and education of diamonds. The combined factors of the 4Cs determine the rarity of each diamond, therefore the value and price. For example, two diamonds of equal carat weight can have very different values depending on the other members of the 4C’s: clarity, color and cut.

How Color Determines a Diamond’s Value:

Diamond color is all about what you can’t see. One way to determine a diamond’s value is by how closely it approaches colorlessness – the less color, the higher their value. (The exception to this is fancy color diamonds, such as pinks and blues, which lie outside this color range.) Most diamonds found in jewelry stores run from colorless to near-colorless, with slight hints of yellow or brown.

GIA’s color-grading scale for diamonds is the industry standard. The scale begins with the letter D, representing colorless, and continues with increasing presence of color to the letter Z, or light yellow or brown. Each letter grade has a clearly defined range of color appearance. Diamonds are color-graded by comparing them to stones of known color under controlled lighting and precise viewing conditions.

Many of these color distinctions are so subtle as to be invisible to the untrained eye. But these slight differences make a very big difference in diamond quality and price.

How Clarity Determines a Diamond’s Value:

Because diamonds form deep within the earth under extreme heat and pressure, they usually contain unique birthmarks, either internal (inclusions) or external (blemishes). Diamond clarity refers to the absence of these inclusions and blemishes. Diamonds without these birthmarks are rare, and rarity effects a diamond’s value.

The GIA International Diamond Grading System™ contains 11 grades, with most diamonds falling into the VS (very slightly included) or SI (slightly included) categories. In determining a diamond’s value using clarity, a skilled grader uses the GIA system and considers the size, nature, position, color or relief, and quantity of clarity characteristics visible under 10× magnification.

• Flawless (FL) – No inclusions or blemishes are visible

• Internally Flawless (IF) – No inclusions and only blemishes are

• Very, Very Slightly Included (VVS1 and VVS2) – Inclusions are difficult to see

• Very Slightly Included (VS1 and VS2) – Inclusions are minor and range from difficult to somewhat easy to see

• Slightly Included (SI1 and SI2) – Inclusions are noticeable

• Included (I1, I2, and I3) – Inclusions are obvious and may affect transparency and brilliance

How Cut Determines a Diamond’s Value:

Cut quality is the factor that fuels a diamond’s fire, sparkle, and brilliance. The allure and beauty of a particular diamond depends more on cut quality than anything else.

The GIA Diamond Cut Grading System for standard round brilliants in the D-to-Z color range is based on the assessment of seven components.

1. Brightness – the total light reflected from a diamond

2. Fire – the dispersion of light into the colors of the spectrum)

3. Scintillation – the pattern of light and dark areas and the flashes of light, or sparkle, when a diamond is moved

4. Weight ratio

5. Durability

6. Polish

7. Symmetry

These first 3 components are appearance-based aspects. The remaining four are related to a diamond’s design and craftsmanship

In GIA’s system, each cut is given a grade based on a scale from Excellent to Poor and represents a range of proportion sets and appearances. There are many different proportion sets that produce attractive diamonds.

It is important to note that a wide range of proportion combinations are possible, and these ultimately effect the stone’s interaction with light and how attractive the diamond is to the person viewing it. An individual’s preferences also play a role. Individuals have the freedom to choose which particular appearance they prefer within the grade range.

Cut vs. Shape: People often use the words cut and shape interchangeably. They think of cut as the shape or outline of the diamond, rather than the arrangement of facets needed to create an attractive appearance.

Round is the shape used in most diamond jewelry. All other outlines are known as fancy shapes. Examples of traditional fancy shapes include the marquise, princess cut, pear and oval. Hearts, triangles and a variety of others are also gaining popularity in diamond jewelry. The diamond’s shape is most often determined by the shape of the rough diamond crystal and by the popularity of certain shapes.

How Carat Weight Determines a Diamond’s Value:

Diamonds and other gemstones are weighed in metric carats: one carat is equal to 0.2 grams, about the same weight as a paperclip. (Don’t confuse carat with karat, as in “18K gold,” which refers to gold purity.)

Just as a dollar is divided into 100 pennies, a carat is divided into 100 points. For example, a 50-point diamond weighs 0.50 carats. The majority of diamonds used in fine jewelry weigh one carat or less.

How did “carat” get it’s name? The carat, the standard unit of weight for diamonds and other gemstones, takes its name from the carob seed. Because these small seeds have a fairly uniform weight, early gem traders used them as counterweights in their balance scales. The modern metric carat, equal to 0.2 grams, was adopted by the United States in 1913 and other countries soon after. Today, a carat weighs exactly the same in every corner of the world.

Carat Weight, Clarity, Cut, & Color All Determine a Diamond’s Value

As we have demonstrated, there are many factors that determine a diamond’s value. Carat weight, cut, clarity, and color are all components that a skilled GIA grader uses when a diamond gets it’s grade.

At FORGE Jewelry Works, our on-site team includes a graduate gemologist and certified diamond graders so you can be sure you are in good hands when you come in to our store as a guest to design your custom engagement ring.