The concept of the 4C’s was developed by GIA in the 1940s and 1950s. The aim was to enable the comparison and evaluation of diamonds. The 4C’s describe a diamond’s key characteristics known as: Carat, Color, Clarity and Cut.
The carat measures the diamond’s weight. One carat is equal to 200mg. Larger diamonds are rarer and therefore of a higher perceived value and more expensive. The price per carat of a diamond is not constant and increases exponentially the bigger the diamond is. E.g. A two carat diamond will cost substantially more than double a one carat diamond.
For common “white”, or colorless, diamonds the Color relates to the degree lack of tint. A chemically pure and structurally perfect diamond is completely transparent and very rare to find. The diamonds’ color differences are almost non-discernible to the human eye. Non-colorless diamonds are referred to as ‘Fancy-colored’, the primary colors being yellow, pink and blue and any combinations thereof. The color of a Fancy -colored diamond is measured both by its appearance to the human eye (its hue) and the intensity (depth) of the color; fancy, fancy intense and vivid. Intense and vivid colored stones are very rare and hence more expensive.
The Clarity of a diamond is defined by its internal defects (“inclusions”) and surface defects (“blemishes”). These imperfections may result from gas, bubbles, cracks or scratches. They can affect the diamond’s ability to properly transmit light, and therefore impact its beauty. The Clarity grade is derived from the total number of inclusions, their size and their location, with their type being of secondary importance. Diamonds with a higher clarity grade are rarer and therefore considered more valuable.
The Cut is the only parameter derived by the human hand. An accurately cut and facetted diamond will reflect most of the light back at the viewer through the top of the stone, causing exceptional Brilliance. A poorly cut diamond creates a duller diamond with less Sparkle and Fire (colored flashes) and will not appear as beautiful. With poor Symmetry, the reflected light will be misdirected as it exits the diamond. The most popular Cut is the round brilliant, as it returns the highest percentage of light.