Principled Diamonds Diamond Guide

To help you choose your ideal stone….

The 4 C’s

Colour

Diamond colour is all about what you can’t see. Diamonds are valued by how closely they approach colourlessness – the less colour, the higher their value. (The exception to this is fancy colour diamonds, such as pinks and blues, which lie outside this colour range.) Most diamonds found in jewellery stores run from colourless to near-colourless, with slight hints of yellow or brown.

Colour Guide

WHY DOES THE GIA COLOUR GRADING SYSTEM START AT D?

Before GIA developed the D-Z Colour Grading Scale, a variety of other systems were loosely applied. These included letters of the alphabet (A, B and C, with multiple A’s for the best stones), Arabic (0, 1, 2, 3) and Roman (I, II, III) numerals, and descriptions such as “gem blue” or “blue white.” The result of all these grading systems was inconsistency and inaccuracy. Because the creators of the GIA Colour Scale wanted to start fresh, without any association with earlier systems, they chose to start with the letter D

Clarity

Because diamonds formed deep within the earth, under extreme heat and pressure, they often contain unique birthmarks, either internal (inclusions) or external (blemishes).

Diamond clarity refers to the absence of these inclusions and blemishes. Diamonds without these birthmarks are rare, and rarity affects a diamond’s value. Using the GIA International Diamond Grading System™, diamonds are assigned a clarity grade that ranges from flawless (FL) to diamonds with obvious inclusions (I3).

Every diamond is unique. None is absolutely perfect under 10× magnification, though some come close. Known as Flawless diamonds, these are exceptionally rare. Most jewellers have never even seen one.

The GIA Clarity Scale contains 11 grades, with most diamonds falling into the VS (very slightly included) or SI (slightly included) categories. In determining a clarity grade, the GIA system considers the size, nature, position, colour or relief, and quantity of clarity characteristics visible under 10× magnification.

Carat Weight

Diamonds and other gemstones are weighed in metric carats: one carat is equal to 0.2 grams, about the same weight as a paperclip. (Don’t confuse carat with karat, as in “18K gold,” which refers to gold purity.)

Just as a Pound is divided into 100 pence, a carat is divided into 100 points. For example, a 50-point diamond weighs 0.50 carats. But two diamonds of equal weight can have very different values depending on the other members of the Four C’s: clarity, colour and cut. The majority of diamonds used in fine jewellery weigh one carat or less.

Cut or Shape

People often use the words cut and shape interchangeably. They think of cut as the shape or outline of the diamond, rather than the arrangement of facets needed to create an attractive face-up appearance.

Round is the shape used in most diamond jewellery. All other outlines are known as fancy shapes. Examples of traditional fancy shapes include the marquise, pear and oval. Hearts, triangles and a variety of others are also gaining popularity in diamond jewellery.

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