The Four C's of Diamond Grading
GIA’s D-to-Z diamond color-grading system measures the degree of 'colorlessness' or 'lack of colour' by comparing a stone under controlled lighting and precise viewing conditions to master stones to established color value. A poor colour grade may have a yellowish or brownish tint. These tints can be nearly impossible to differentiate to the untrained eye. The diamond colour scale above shows the very subtle difference in colour between diamonds graded D to M. Consider the difference between G to H colour, where you’ll start to see a yellow tint, strengthening in intensity right down to Z.
Many factors can affect clarity. A diamond can hold a vatiety of inclusions from fractures to small crystals these are mostly not visable to the naked eye. The size, position and visibility of inclusions can have a significant impact on diamond clarity. This may also affect a diamonds beauty and durability. A clarirty grade will reflect this. The GIA Diamond Clarity Scale has 6 categories, some of which are divided, for a total of 11 specific grades.
A diamond's cut is often considered the most important characteristic to consider when choosing a diamond, according to most gemmologists. Diamonds graded Excellent by GIA standards have the best angle, symmetry, proportion, balance of facets, and polish that a diamond cutter can achieve. An expertly cut diamond reflects light perfectly, giving off the maximum amount of radiance, fire, and sparkle. Through centuries of study and experimentation, we have gained a better understanding of how reflection and refraction of light work within a diamond. As a result, diamonds can now be cut to a high degree of precision that maximises their natural brilliance and fire.
The 'carat' refers to the weight of a particular gemstone. 1 carat equates to 0.2 grams. For mounted gemstones we can calculate an estimated carat weight using a precision gauge to measure dimensions.