Diamond grading determines the dollar value. It is based on the “4 C’s”: Color, Clarity and Cut (proportion, polish and symmetry), which are the quality elements, together with the Carat weight determine value of a stone. Each element is based on a scale. The closer a diamond grades to the left of one or all of the scales, the rarer and more valuable the stone. Clarity is frequently assumed the most important. However, color and cut, especially cut, have the greatest affect on the appearance of a diamond.
Clarity refers to a stones relative position on a flawless-to-perfect scale. Clarity characteristics are classified as inclusions (internal) or blemished (external). The size, quantity, position, nature, color and relief of the characteristics determine the clarity grade.
|FL||Flawless||Free from all inclusions or blemishes.|
|IF||Internally Flawless||No inclusions visible at 10x magnification|
|VVS1||Very Very Small inclusion #1||Inclusions that are extremely difficult to locate at 10x.|
|VVS2||Very Very Small inclusion #2||Inclusions that are very difficult to locate at 10x.|
|VS1||Very Small Inclusion #1||Minor inclusions that are difficult to locate at 10x.|
|VS2||Very Small Inclusion #2||Minor inclusions that are somewhat difficult to locate at 10x.|
|SI1||Small Inclusion #1||Noticeable inclusions that are easy to locate at 10x.|
|SI2||Small Inclusion #2||Noticeable inclusions that are very easy to locate at 10x. Some inclusions may be seen with the unaided eye.|
|SI3||Small Inclusion #3||Noticeable inclusions that are extremely easy to locate at 10X. Some inclusions may be seen with the unaided eye.|
|I1||Included #1||Obvious inclusions. Somewhat easy to locate with the unaided eye.|
|I2||Included #2||Obvious inclusions. Easy to locate with the unaided eye.|
|I3||Included #3||Obvious inclusions. Very easy to locate with the unaided eye.|
The cut of a diamond greatly determines its brilliance. A cut grade is based on a collection of measurements and observations that determine the relationship between a diamond's light performance, dimensions and finish. Most gemologists consider cut the most important diamond characteristic. High quality diamonds are cut to strict proportions. As a result, they are extremely bright and beautiful. If the cut on a high quality diamond is fair or poor than the diamond lacks brilliance.
Determining a diamond's cut grade, goes beyond simple measurements of width and depth. Using a proportion analyzing device, a three-dimensional model is created to determine the diamond's proportions and angles. The relationships between the various dimensions greatly affect light’s reaction once it enters and exits the diamond. Sophisticated computer software and hardware allows light tracing to measure the levels of brightness, fire and scintillation.
Polish and Symmetry are two important aspects of the cutting process.
Polish grade describes the quality of the diamond's facet surface and symmetry grade refers to facet alignment. Diamonds with a poor polish are dull.
Diamonds with poor symmetry leak light, which results in light rays escaping through the pavilion (lower half of the stone). Light is not reflected back to the viewer’s eye, limiting a diamond’s sparkle.
Cut scale for Proportion, Polish and Symmetry is divided into following grades:
Ideal (ID), Excellent ( EX), Very Good(VG), Good(GD), Fair(F) and Poor(P).
Grading color in the normal range involves determining how close a stone’s color approaches colorlessness. Most diamonds have a trace of yellow or brown body color, with exception of some natural fancy colors, such as blue, pink or red. The colorless grade is the most valuable. Fluorescence (define) can enhance the perceived color.
The final aspect of grading a diamond is the carat. Carat is a metric unit of weight in the gem stone industry. Carat is equal to 1/5th of a gram or “5 carats in a 1 gram.” The term “points” is a decimal fraction of a carat. A point is equal to .01 (1/100th) of a carat. Just as 1 dollar is equal to 100 cents, 1 carat equals 100 points.
1 Carat = 100 Points = 200 milligrams
Generally speaking, larger stones are rarer than smaller stones of the same quality. This is why the 1 carat, 20 stone cluster ring is less expensive than a 1 carat solitaire of the same quality. The size at which a gemstone increases significantly in price varies with the availability.
Carat weight and the physical size of a stone vary between species of gemstones. For example, a carat round diamond is 6.5 millimeters in diameter, but a 1 carat ruby is 5.5 to 6.0 millimeters in diameter. This is because rubies are denser and typically cut heavier than a diamond. So, a 1.5 carat stone may be needed to replace the mounting of a 1 carat diamond. Physical measurements rather than carat weight should be used to match size.
Fluorescence in Diamonds, some people like the effect while others do not, in usual circumstances it is never seen unless the diamond displays a very high fluorescence, though if a diamond that displays usual fluorescence is exposed to direct or intense ultraviolet light a bluish glow can be observed. Strong fluorescence can lower the price of a Diamond, but in some case may even lift the color one grade to the naked eye so to add to the beauty, or even detract from the diamond giving it a slightly hazy appearance. It's one factor that should be check with the individual opinion depending on the amount of fluorescence displayed.
Listed below are the grade scales for describing strength of fluorescence that should be noted when reading a diamond grading report:
Diamond Grading Report
Whilst the acquisition of diamond jewelry is an important expression of love or accomplishment, it also represents a major investment in time, energy and money. You need and deserve to feel confident in the integrity of what you've acquired. After all, whilst two gems may LOOK identical to the untrained eye, they may be quite different in quality....and worlds apart in value.
The only way to ensure the quality of your diamond is to purchase a diamond accompanied with an independent diamond grading report. We provide GIA, IGI, HRD and EGL certification as these are some of the most respected and trusted diamond laboratories in the world. A diamond grading report is essentially a statement attesting to the authenticity of a diamond it provides a true and accurate statement of the diamonds characteristics and grade based on internationally recognized standards.
A diamond grading report will includes a plotted diagram of the diamond and all significant characteristics, cut, color, clarity, carat weight. The report also describes the diamond's shape, exact measurements and proportions as well as grade the polish and symmetry. The report comments on the distinctiveness of the diamond, like fluorescence if present, graining, and any imperfections the diamond may have.EGL - EUROPEAN GEMOLOGICAL LABORATORY - www.eglindia.biz
EGL is one of the largest and oldest independent gemological institutions focusing on gemstone certification and research.
IGI - INTERNATIONAL GEMOLOGICAL INSTITUTE - www.igiworldwide.com
Founded in 1975, the IGI is one of the world's foremost diamond laboratories. Each diamond is scientifically analyzed by several gemologists who, using the latest state-of-the-art equipment, provide an accurate description of the characteristics of the diamond and quality of its cut. The IGI issues approximately 1 million diamond grading reports each year.
GIA - GEMOLOGICAL INSTITUTE OF AMERICA - www.gia.edu
The GIA is known for having the most strict, consistent and unbiased systems for grading diamonds. Diamonds that are supplied with these diamond grading reports are the most highly valued in the industry as their quality is considered guaranteed. Indeed, it was the GIA who, over 70 years ago, founded the international diamond grading system which is today used across the world. The GIA provides 2 types of report: