The 4Cs - Cut
The cut of a diamond is the only one of the 4Cs that is influenced by hand. The quality of cut significantly affects a diamond's brilliance and lustre (brightness due to white light being reflected), it's fire (the scattering of white light into all the colours of the rainbow), and it's scintillation (sparkle). A well cut diamond can make light dance in breathtaking ways, whilst a poorly cut diamond can look dark and dull.
When grading a diamond's cut, a number of factors are taken into consideration - the proportions (relationship between diameter, crown height, depth, crown, pavilion angles and girdle), culet size, girdle thickness - which can affect a diamond's durability, polish and symmetry of the facets. The proportions and girdle thickness of a poorly cut diamond may result in the diamond looking smaller than a well cut diamond of the same carat weight, as carat only refers to the weight of the stone and not the diameter.
For us, there's nothing better than watching a beautiful, bright diamond sparkle and reflect rainbows of colour with your every movement and it's for this reason that we only stock diamonds with a minimum of a Very Good cut.
GIA DIAMOND CUT GRADING SCALE
Use the slider and browse the images to explore the differences between diamonds with Excellent, Very Good, Fair and Poor cuts.
GIA have produced a video on cut grading, which is highly recommend if you are still seeking further information on how GIA grades a diamond's cut.