The Four C's of Diamonds
Cut fuels the diamond's fire, sparkle, and brilliance.
Without a doubt, the allure of a particular diamond depends more on cut than anything else. Though extremely difficult to analyze, the cut of a diamond has three attributes: brightness (the total light reflected from a diamond), fire (the dispersion of light into the colors of the spectrum), and scintillation (the light flashes or sparkle when a diamond moves). An understanding of diamond cut begins with the shape of a diamond, with the standard round brilliant dominating the majority of diamond jewelry. Other popular shapes or cuts include princess, oval, cushion and emerald cuts.
The Color of the diamond is all about what you can't see.
Diamonds are valued by how closely they approach colorlessness i.e. the less color, the higher the value. Most diamonds found in jewelry stores run from colorless to near-colorless with slight hints of yellow or brown. The only exceptions are the fancy-color diamonds that lie outside of this range.
The Gemological Institute of America's (GIA) diamond color-grading scale is the industry's most widely accepted grading system. The scale begins with the letter D, representing colorless, and continues, with increasing presence of color, to the letter Z. Many of these color distinctions are so subtle that they are invisible to the untrained eye. But these slight color differences make a very big difference in diamond quality and price.
Diamond Clarity refers to the absence of internal inclusions or external blemishes.
Because they are created deep within the earth, most diamonds contain unique birthmarks called inclusions (internal) and blemishes (external). Diamonds with very few birthmarks are rare and, of course, rarity affects a diamond's value. Using the International Diamond Grading System, created by GIA, diamonds are given a clarity grade that ranges from flawless to diamonds with more prominent inclusions. In determining a clarity grade, GIA considers the size, nature, position, color or relief, and quantity of clarity characteristics visible under 10x magnification.
Carat - Weight
Carat weight is the most intuitive of the 4Cs. You expect a larger diamond to be worth more when assigning diamond values.
Just as a dollar is divided into 100 pennies, a carat is divided into 100 points which means that a diamond of 50 points weighs 0.50 carats. But two diamonds of equal weight can have very different values depending on the other three characteristics of a diamond's 4Cs: cut, color, and clarity. The majority of diamonds used in fine jewelry weigh one carat or less.