Diamond facet with numerous pits. Pitted facets affect the polish grade of a diamond.
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.
Pinpoints
Very tiny diamond crystal inclusions that are too small in size to distinguish their individual shapes. One pinpoint looks like a small “dot” under 10x magnification. Clusters of pinpoints create a cloud.
Pit
Type of diamond blemish that appears as a tiny opening or indentation on the surface of a diamond. Large pits are called cavities. Pits affect the polish grade of a diamond.
Phosphorescence
Phenomenon that causes some diamonds to continue “glowing in the dark,” after a light source is removed. Phosphorescence is much more common in synthetic diamonds than in natural diamonds.
Pink Diamond
A coloured diamond with a natural pink body colour. Pink must be the predominant colour, but it may be modified by shades of purple, orange, and yellow. The colour in natural pink diamonds is created by irregular crystal structure. Some pink coloured diamonds with sufficient saturation fall into the valuable fancy pink colour category of diamonds.
Pear Cut
Diamond cut or shaped into the outline of a tear-drop or a pear, with a rounded head tapering to a point.
Pavilion Depth Percentage
Pavilion depth expressed as a percentage of the diameter. Pavilion depth is an extremely important proportion to the brilliance of a diamond; diamonds with a pavilion that is too deep will have a nailhead, while diamonds with a pavilion that is too shallow or flat will have a fish eye.
Pavilion Main Facets
Pavilion Angle
Angle measured between the girdle plane and the pavilion main facets.