The 4Cs of Diamond Quality

Understanding the 4Cs—Cut, Color, Clarity, and Carat Weight—is essential to evaluating diamond quality and value. Developed by GIA and adopted by IGI and other gemological institutes worldwide, this universal grading system helps you make informed decisions when selecting the perfect diamond.

Cut: The Most Important C

Cut is the most important factor in a diamond's beauty. It determines how well a diamond interacts with light, creating the brilliance, fire, and scintillation that make diamonds captivating. A well-cut diamond reflects light internally from facet to facet and disperses it through the crown, while a poorly cut diamond allows light to escape through the sides or bottom, appearing dull even with excellent color and clarity.

Explore Cut Grades
Ideal
Poor
Light escapes through sides and bottom
Fair
Limited brilliance and fire
Good
Reflects most light entering
Very Good
Excellent brilliance and sparkle
Ideal
Maximum brilliance and fire
GIA & IGI Standards
Both GIA and IGI evaluate cut quality based on proportions, symmetry, and polish. A well-cut diamond reflects light from one facet to another and disperses it through the top, creating the sparkle and brilliance that makes diamonds so desirable. Cut is the only C directly influenced by human craftsmanship.

Color: From Colorless to Light Yellow

Diamond color grading evaluates the absence of color in white diamonds. The GIA and IGI color scale ranges from D (colorless) to Z (light yellow or brown). Colorless diamonds (D-F) are the rarest and most valuable, while near-colorless diamonds (G-J) offer excellent value as their slight color is often undetectable when mounted in jewelry.

Explore Color Grades
G-H
D-E-F
Colorless - Highest grade
G-H
Near colorless - Excellent value
I-J
Near colorless - Good value
K-L-M
Faint color - Budget friendly
N-O-P-Q-R
Very light color
S-T-U-V-W-X
Light color
Y-Z
Light yellow
GIA & IGI Color Grading
Both GIA and IGI use the D-Z color scale for white diamonds. The scale begins with D (colorless) and continues to Z (light yellow or brown). Diamonds are graded by comparing them to master stones under controlled lighting and viewing conditions. The differences between grades can be very subtle and often invisible to the untrained eye.
D-F Colorless
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Icy white appearance
G-J Near Colorless
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Appears colorless when mounted
K-M Faint
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Slight warmth visible

Clarity: Nature's Fingerprint

Clarity refers to the presence of internal inclusions and external blemishes in a diamond. These natural characteristics formed during the diamond's crystallization process deep within the earth. GIA and IGI grade clarity under 10x magnification, ranging from Flawless (no inclusions visible) to Included (inclusions visible to the naked eye). Each diamond's clarity characteristics are unique, like a fingerprint.

Explore Clarity Grades
VS2
FL
Flawless - No inclusions
IF
Internally Flawless
VVS1
Very Very Slightly Included
VVS2
Very Very Slightly Included
VS1
Very Slightly Included
VS2
Very Slightly Included
SI1
Slightly Included
SI2
Slightly Included
I1
Included - Visible to eye
I2
Included - Easily visible
I3
Included - Obvious inclusions
Understanding Clarity Grading
GIA and IGI clarity grading is based on the visibility of inclusions and blemishes when viewed under 10x magnification. Inclusions are internal characteristics like crystals, feathers, or clouds, while blemishes are external marks. Most inclusions in VS and higher grades are invisible to the naked eye, making these grades excellent value choices.

Carat Weight: Size and Presence

Carat weight measures a diamond's mass, not its size. One carat equals 200 milligrams. While carat weight influences a diamond's size, two diamonds of equal weight can appear different in size depending on their cut proportions and shape. The relationship between carat weight and price is not linear—larger diamonds are exponentially more expensive because they are rarer in nature.

Explore Carat Weights
1.00 ct
0.50 Carat
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5.2mm diameter
1.00 Carat
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6.5mm diameter
2.00 Carat
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8.2mm diameter
Carat Weight Facts
One carat equals 200 milligrams or 0.2 grams. Carat weight is divided into 100 points, so a 0.75 carat diamond is also called a 75-point diamond. While carat weight affects size, two diamonds of equal weight can have different values based on cut, color, and clarity. Additionally, well-cut diamonds can appear larger than their actual carat weight suggests.
Price Per Carat
Diamond prices increase exponentially with carat weight because larger diamonds are rarer. A 2-carat diamond costs more than twice as much as a 1-carat diamond of the same quality. Magic sizes like 0.50, 1.00, and 2.00 carats command premium prices, so choosing slightly below these weights can offer significant savings.

Making Your Diamond Decision

The 4Cs work together to determine a diamond's overall quality and value. While each C is important, prioritize based on your preferences and budget. Many experts recommend prioritizing cut quality first, as it has the greatest impact on a diamond's beauty. Always purchase diamonds certified by reputable laboratories like GIA or IGI to ensure accurate grading and quality assurance.