When trying to understand and study a diamond it is important to learn about each of its different parts. We like to think of a fine diamond like a powerful engine in a car. The engines strength is the sum of its parts working in unison to push it forward. Better and more well aligned parts produce more fire, scintillation and thus, a more brilliant and valuable diamond. Let’s study the map of the diamond below outlining its important parts and how they relate to each other.
Area between the tab. and girdle.
Resting at the top of a diamond, the table is the largest, most visible facet.The measurement of a diamond from the center of the table through its culet
This angle is the final stop before light is reflected back toward your eye. If this key transition is too sharp then the light will be cast downward and the diamond will appear lifeless when viewed from above. If it is too large light will escape the crown greatly affecting a diamond, fire and brilliance.
PAVILION ANGLEMuch like the crown angle the pavilion angle is essential to the collection and subsequent refraction of light. Too shallow and light not reflect toward the crown leading to a dull appearance. If the angle is too deep precious light will escape prematurely at the expense of brilliance.
DEPTH The measurement of a diamond from the center of the table through its culet
GIRDLEThe small area separating the crown of the diamond from the pavilion of the diamond. On a round brilliant diamond the girdle is scalloped with hills and valleys. A thicker girdle contributes to overall depth percentage. This greater depth may add weight and therefore cost without improving the face-up appearance of a diamond. Traditionally the girdle has a frosted appearance but some cutters will micro facet them to give a finished look.
The ratio of the diamond’s largest and most prominent facet located on the top of the diamond relative to its overall width. The total diameter is equal to 100% while the size of the table is measured in relation to it. The table and depth percentages are the most important measurements when determining the overall cut grade and light performance of a diamond.
The ratio of a diamond’s depth and its overall diameter. It is measured by taking the distance between the top of the diamond known as it’s table, and the very bottom point of the diamond known as it’s culet. This is always described as a percentage of its overall diameter which equates to a fraction of the total diameter. The table and depth percentages are the most important measurements when determining the overall cut grade and light performance of a diamond.
Polish refers to how smooth each of a diamond’s facets are. During the process of faceting a rough diamond to a finished diamond minor, microscopic imperfections can appear on the surface of the facets. The quality of diamond’s polish is determined by a grader under 10x magnification based on the quality of its surface finish.
The symmetry of a diamond relates to how well its facets are shaped and aligned in relation to one another. A diamond with poor symmetry may exhibit light leakage which will compromise its ability to properly reflect and refract light.
Diamond fluorescence is a common characteristics found in about one third of all diamonds. It refers to the soft glow emitted when ultraviolet (UV) light is exposed to it. While there are several colors in diamond fluorescence blue is by far the most common. Only about 10% of diamonds exhibiting fluorescence experience a change to their overall appearance. In some cases, these changes manifest in a slightly hazy or milky appearance. It is more common, however for blue fluorescence to improve the diamonds visual appearance when exposed to daylight.