Color
Diamond color is all about what you can’t see. Diamonds are valued by how closely they approach 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 sets the benchmark with its diamond color-grading scale, starting at D for colorless and progressing towards Z for light yellow or brown hues. Each letter grade delineates a distinct range of color appearance. Diamonds undergo color grading by comparison with stones of known color under controlled lighting and precise viewing conditions.
These subtle color differentiations, often invisible to the untrained eye, significantly impact the quality and price of a diamond.
Cut
Cut quality is the primary factor behind a diamond's brilliance and sparkle, often surpassing all other considerations in its allure and beauty. The GIA Diamond Cut Grading System evaluates standard round brilliants in the D-to-Z color range based on seven key components.
The first three components—brightness, fire, and scintillation—relate to the diamond's appearance, reflecting its total light, color dispersion, and pattern of sparkle. The remaining four factors—weight ratio, durability, polish, and symmetry—pertain to the diamond's design and craftsmanship. Each component is individually assessed within GIA's system, considering its relative importance to the overall cut quality. The resulting cut grades range from Excellent to Poor, representing various proportion sets and face-up appearances. These proportions, including table size, crown angle, and pavilion depth, significantly influence how the diamond interacts with light, shaping its attractiveness to the observer.
Consider a side view of the standard round brilliant diamond, showcasing its main components: the crown, girdle, and pavilion. This cut typically features 57 or 58 facets, with the 58th facet known as the culet, a tiny flat facet at the pavilion's base. At the top lies the table, a large, flat facet. Diamond proportions involve the relationships between table size, crown angle, and pavilion depth, crucial for how the stone interacts with light and its appeal to the viewer.
Carat
Gemstones, including diamonds, are measured in metric carats, where one carat equals 0.2 grams, approximately the weight of a paperclip. It's important not to confuse "carat" with "karat," as in "18K gold," which denotes gold purity.
Similar to how a dollar divides into 100 pennies, a carat divides into 100 points. For instance, a 50-point diamond weighs 0.50 carats. However, two diamonds of equal weight can hold vastly different values based on the other components of the Four C's: clarity, color, and cut. The majority of diamonds utilized in fine jewelry are one carat or smaller. Given that even a fraction of a carat can significantly impact cost, precision is paramount. In the diamond trade, weight is often measured down to the hundred-thousandths of a carat, then rounded to the nearest hundredth of a carat. Diamonds weighing more than one carat are expressed in carats and decimals. For example, a 1.08 carat stone would be stated as "one point zero eight carats," or "one oh eight."
Clarity
Diamonds are formed deep within the earth's intense heat and pressure, often resulting in distinct birthmarks, either internally (inclusions) or externally (blemishes).
Clarity in diamonds signifies the absence of these birthmarks. Truly flawless diamonds, devoid of these features, are exceedingly rare and thus hold great value.
Each diamond is uniquw. Though no diamond is perfectly flawless under 10× magnification, some come remarkably close, termed Flawless diamonds—a rarity so profound that many jewelers have never encountered one.
Using the GIA International Diamond Grading System™, diamonds are categorized into clarity grades, ranging from flawless (FL) to those with evident inclusions (I3).
Flawless (FL) - No inclusions or blemishes are visible to a skilled grader using 10× magnification
Internally Flawless (IF) - No inclusions and only blemishes are visible to a skilled grader using 10× magnification
Very, Very Slightly Included (VVS1 and VVS2) - Inclusions are difficult for a skilled grader to see under 10× magnification
Very Slightly Included (VS1 and VS2) - Inclusions are minor and range from difficult to somewhat easy for a skilled grader to see under 10x magnification
Slightly Included (SI1 and SI2) - Inclusions are noticeable to a skilled grader under 10x magnification
Included (I1, I2, and I3) - Inclusions are obvious under 10× magnification and may affect transparency and brilliance
Our insights are inspired by Gemological Institute of America (GIA) educational resources. Discover more about diamond quality at GIA 4Cs Diamond Quality
