A coloured diamond with a natural red body colour. Red must be the predominant colour, but it may be modified by shades of pink or purple. The colour in natural red diamonds is created by irregular crystal structure. Natural red diamonds are the most rare of all diamonds. Some red coloured diamonds with sufficient saturation fall into the valuable fancy red colour category of diamonds.
Radiant Cut
Diamond cut or shaped into a square or rectangular princess cut, with the corners cut off.
Proportions
Relations between the dimensions and angles of a finished diamond. Examples of specific proportions are table size, depth percentage, and crown angle. Proportions are extremely important to the beauty, brilliance, and life in a diamond. Click here to learn more about proportions on a diamond grading report.
Proportion Grade
Qualitative analysis of the overall proportions on a round brilliant cut diamond. Fancy shaped diamonds are not proportion graded; unlike round cut diamonds, there is no defined range of proportion standards for fancy shapes.
Princess Cut
Diamond cut or shaped into a square or rectangle. Princess cuts combine features of both step cut and brilliant cut diamonds.
Polished Girdle
Describes the girdle of a diamond that has been fully polished smooth and clear around the entire perimeter. Step cut diamonds such as emerald cut and baguette cut diamonds usually have a polished girdle, and some brilliant cut diamonds may have polished girdles as well.
Polish Grade
Qualitative analysis of the overall surface condition of a diamond. The quality of polish is determined by the care put in by a polisher when finishing a diamond, and is important to the brilliance and scintillation given off by a diamond.
Point
Term for one hundredth of a carat. For example, a fifteen-point diamond weighs 0.15 carats. It could also be called a fifteen “pointer”.
Plotting Diagram or “Plotâ€
Diagram of the approximate relative size, location, and type of internal inclusions and external blemishes of a diamond. A plotting diagram is often used for identifying a particular diamond.
Pitted Facet
Diamond facet with numerous pits. Pitted facets affect the polish grade of a diamond.