Why Diamonds Are Graded From D-to-Z

It’s a given that the colour of your gemstone is a major factor into both its personal enjoyment and market value. When we’re thinking of diamonds, it’s generally believed that the bulk of the stones you see are colourless, but in actuality, many of the crystal-clear pieces you see in stores can take on subtle reflections of yellow and brown. Even the slightest trace of one of these colours can affect the price of a diamond, which is why dealers and professionals turn to a colour-grade scale to determine a stone’s inherent value.

The industry-standard for grading diamonds was created by the Gemological Institute of America, and is used primarily to determine the value and colour of a diamond. The scale starts at D, which rates a diamond as truly colourless, and runs up to Z, which would denote a light yellow or brown stone. Each grade denotes a gradual increase in colour. This scale, however, doesn’t apply to fancy colour diamonds like pink, red, blue, or violet, which can be extremely valuable in their own right.

The difference between a pure, colourless diamond and a yellow diamond will be noticeable to most, but the subtle differences between these two poles will generally be untraceable to the naked, untrained eye. The GIA’s colour scale, however, is a rigid, clear-defined system where professionals will compare the stone in question to previously-graded stones under precise, controlled lighting conditions. Only then can they determine which letter grade to give a diamond, and properly set a price for the stone.

While pure, colourless diamond is seen as the industry standard, a slightly-coloured diamond isn’t worthless. Far from it! Yellow diamond, for instance, has been trending lately as both a more-affordable an equally stunning gem, while fancy colour diamonds like blue and red are especially rare and valuable, even compared to the purest, colourless diamond. The GIA colour scale may pinpoint the market value, but finding the right diamond for you, regardless of colour, is truly priceless.

Source:

https://www.gia.edu/gia-about-4Cs-Color