What is a GIA Certificate?
A GIA diamond certificate, also called a diamond grading report, diamond dossier®, or diamond quality document, is a report created by a team of gemologists at GIA which is the world renouned Gemological Institute of America. The GIA certifies the dimonds and grades them based on the DIAMOND CUT, DIAMOND CLARITY, DIMOND COLOR AND DIAMOND CARAT WEIGHT.
The diamond is evaluated, measured, and scrutinized using trained eyes, a jeweler’s loupe, a microscope, and other industry tools. A completed certificate includes an analysis of the diamond’s dimensions, clarity, color, polish, symmetry, and other characteristics. Many round diamonds will also include a cut grade on the report.
Cut is the factor that fuels a diamond’s fire, sparkle and brilliance.
The traditional 58 facets in a round brilliant diamond, each precisely cut and defined, are as small as two millimeters in diameter. But without this precision, a diamond wouldn’t be nearly as beautiful. The allure of a particular diamond depends more on cut than anything else.
Though extremely difficult to analyze or quantify, the cut of any diamond has three attributes: brilliance (the total light reflected from a diamond), fire (the dispersion of light into the colors of the spectrum), and scintillation (the pattern of light and dark areas and the flashes of light, or sparkle, when a diamond is moved).
Because diamonds formed deep within the earth, under extreme heat and pressure, they often 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 affects a diamond’s value. Using the GIA International Diamond Grading System™, diamonds are assigned a clarity grade that ranges from flawless (FL) to diamonds with obvious inclusions (I3).
Every diamond is unique. None is absolutely perfect under 10× magnification, though some come close. Known as Flawless diamonds, these are exceptionally rare. Most jewelers have never even seen one.
The GIA Clarity Scale contains 11 grades, with most diamonds falling into the VS (very slightly included) or SI (slightly included) categories. In determining a clarity grade, the GIA system 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 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
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’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.
DIMOND CARAT WEIGHT
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. But two diamonds of equal weight can have very different values depending on the other members of the Four C’s: clarity, color and cut. The majority of diamonds used in fine jewelry weigh one carat or less.
Because even a fraction of a carat can make a considerable difference in cost, precision is crucial. In the diamond industry, weight is often measured to the hundred thousandths of a carat, and rounded to a hundredth of a carat. Diamond weights greater than one carat are expressed in carats and decimals. (For instance, a 1.08 ct. stone would be described as “one point oh eight carats,” or “one oh eight.”)