Selecting the perfect diamond for you starts with a little education. We begin here with the 4 C’s: Carat, Cut, Color, and Clarity. Diamond experts explain how to choose the right diamond for you.
MEASUREMENT & PROPORTIONS
The Diamond measurement and proportions define a diamond’s overall visual appeal. Some diamonds are cut to emphasize the total carat weight, while others are designed to enhance brilliance and luster. Gemologists use these measures to precisely measure each diamond’s unique personality.
The top facet of a diamond is the table. If the table is out of proportion to the body of the jewel, it will negatively affect the brilliance and fire.
Depth of a diamond is measured by drawing an imaginary line between the cnter of the Top (table) and bottom (culet) facets.
The bottom point or facet of the diamond is the culet. A small, flat face at the culet is undesirable for a round cut diamond, but may provide positive characteristics for other shapes and styles.
When a diamond’s crown is cut at an ideal angle, the jewel will yield optimal sparkle and fire. If the crown angle is too steep, the jewel will display limited sparkle when viewed from overhead. If the crown angle is too shallow, the diamond could seem flat and translucent.
The girdle is typically a thin edge of the diamond where it can be held by the setting.
Much like the crown angle, the pavilion affects sparkle and brilliance. When cut properly, the pavilion will emit the most sparkle through the top of the jewel. Cutting too shallow limits sparkle and makes the diamond seem glasslike. If the angle is too large the diamond will not emit optimal sparkle.
CREATING LIGHT & SPARKLE
Depth percentage expresses a width to depth ratio for the diamond, and is a key determinant in grading a stone cut. The depth of the stone from Table to Culet should measure between 58% and 64% of the diameter across the width of the girdle to maximize sparkle emitted.
The width of the table (top facet) in relation to the overall diameter of the diamond establishes the Diamond table percentage. Too large, and the Diamond can appear flat and translucent. The ideal proportions of a diamond table percentage is within the range of 53% to 58%, Excellent is 58.1% to 60% and Good range between 60.1% to 64%.
Grading for polish quality refers to the overall craftsmanship of the finished diamond. Are the edges sharp? Are the facets smooth and flat? Polishing wheel marks should not be visible without magnification.
ADDITIONAL DIAMOND GRADING CRITERIA
Symmetrical diamonds reflect more light, adding to the overall sparkle. Gemologists review more than 20 different symmetry features in order to grade how perfectly the facets and cut angles align.
Fluorescence measures the color of the light emitted by a diamond under an ultraviolet light. While diamond professionals often prefer a fluorescence grade of “none”, “Faint” or “Medium” grades will offer a better value in lower diamond colors.
THE DIAMONDS CERTIFICATE
A certification is an independent quality report on a specific diamond. It is issued by a diamond grading laboratory with no affiliation to any retail outlet, giving the consumer a completely objective opinion on the diamond’s quality. The certification includes the exact measurements, proportions, color grade, clarity grade, cut grade and carat weight of the diamond. It also includes specifics that most jewelers do not have the equipment or the knowledge to determine, such as the diamond’s fluorescence, polish, and symmetry. Each certification has it’s own number, the date which it was analyzed and a plotting of the diamond which shows the internal and external characteristics of the diamond. The leading diamond laboratory in the world and the one that is setting the Diamond grading standard is the Gemological Institute of America (G.I.A.).