There is no other gemstone quite like a diamond. It is found in the most remote places on earth, and the fact that it forms at all is something of a miracle. It takes about one ton of rock to recover less than half a carat of rough, making diamond one of the rarest and most desired gemstones in the world. A diamond is a testament of endurance and strength – and not surprisingly, the ultimate symbol of love.
Every diamond is unique. Each reflects the story of its arduous journey from deep inside the earth to a cherished object of adornment. Yet all diamonds share certain features that allow us to compare and evaluate them. These features are called the 4Cs.
Independent and nonprofit, GIA is considered the final word on a diamond’s authenticity and quality. GIA developed the 4Cs and the International Diamond Grading System™, the grading standard adopted by jewelry professionals around the globe. GIA screens every gemstone to identify synthetics, simulants and known treatments. Expert gemologists examine each diamond under controlled lighting and viewing conditions, in order to provide the most rigorous assessments of a diamond’s 4Cs. Every GIA Diamond Grading Report or Diamond Dossier® contains these assessments along with additional descriptive information and state-of-the-art security features. Regarded as premier gemological credentials by international gem professionals and fine jewelry houses, GIA Reports accompany the world’s most legendary diamonds – and now, quite possibly, yours.
The GIA Color Scale extends from D (colorless) to Z (light yellow or brown). Although many people think of gem quality diamonds as colorless, truly colorless diamonds are actually very rare. Most diamonds used in jewelry are nearly colorless with tints of yellow or brown.
Color grades are determined by comparing each diamond to a master set. Each letter grade represents a range of color and is a measure of how noticeable a color is. Fluorescence Some diamonds can emit a visible light when exposed to ultraviolet radiation, but fluorescence is not a factor in determining color or clarity grades. However, a description of its strength and color is provided on GIA Reports as an additional identifying characteristic.
The GIA Clarity Scale includes eleven clarity grades ranging from Flawless to I3. Because diamonds form under tremendous heat and pressure, it is extremely rare to find a diamond that lacks any internal and external characteristics. These characteristics are a by-product of its formation and help gemologists separate natural diamonds from synthetics and simulants, and identify individual stones.
The GIA Cut Scale ranges from Excellent to Poor. GIA provides a cut quality grade for standard round brilliant diamonds that fall in the GIA D-to-Z color range.
A polished diamond’s beauty lies in its complex relationship with light: how light strikes the surface, how much enters the diamond, and how, and in what form light returns to your eye. The result is a magnificent display of three attributes. Brightness is the combination of all white light reflecting from the surface and interior of a diamond. Fire describes the “flares” of color emitted from a diamond. Scintillation describes the flashes of light you see when the diamond, the light, or the observer moves.
A polished diamond’s proportions affect its light performance, which in turn affects its beauty and overall appeal. Diamonds with fine proportions, symmetry, and polish optimize their interaction with light, and have increased brightness, fire, and scintillation.
One carat equals 200 milligrams in weight. For diamonds under one carat, each carat is divided into 100 points – similar to pennies in a dollar. 0.75 ct. = 75 points, 1/2 ct. = 50 points.
The 4Cs provide a way to objectively compare and evaluate diamonds, but numbers alone can’t describe a diamond’s mysterious and captivating beauty – for that, you’ll have to visit your local jeweler to see one for yourself.
To learn more about the 4Cs, GIA, its reports and services, visit www.gia.edu