A Diamond "Cut" is consider by many to be a diamond's most important characteristic, Since It has the greatest overall influence on a diamond's beauty.
Only when precisely calculated planes and angles are used, does the diamond achieve its greatest possible beauty.
Many poorly cut diamonds these days may carry a very high color and clarity grades, but will not compare in the sparkle and brilliance of a better-cut diamond with comparatively lower color and clarity.
It's a simple fact that can be proven by simple science. Please view the image below as you keep reading.
Crown: The top portion of the diamond, from the girdle to the table.
Pavilion: The lower portion of a diamond, from the girdle to the culet.
Culet: The facet or point at the bottom of the diamond's pavilion.
Girdle: The narrow rim around the widest part of a diamond, separating the crown from the pavilion.
Depth: The height of a gemstone, from the culet to the table. Determined as a percentage of the overall diameter of the stone.
Experts express differing opinions on the best "table size" (the diameter of the largest facet on the top of the stone), and the best "Depth" for a diamond, because these factors alone are not sufficient to accurately judge its cut.
Other factors like: - crown angle, girdle thickness, pavilion depth-percentage (the ratio of depth to girdle diameter), culet size, polish and symmetry - also play a major role in judging a diamond's overall cut quality as these factors highly effect "the behavior of light" in diamonds.
Understanding The Behavior Of Light In Diamonds
Though color, clarity, and carat also contribute to a diamond's appeal, it's the cut that determines the symmetry of the stone facets, overall proportions and ability to reflect light.
To better understand a "very good" & "excellent" diamond cuts, it helps to understand how light reacts within a diamond.
There are many shapes that diamonds are cut like round, oval, pear, heart, marquise, emerald or princess. Ideally the diamond cut is done in a way to best reflect the light that shines into it. A well cut diamond internally reflects light from one facet to another, disperse and reflect it through the top of the stone maximizing the brilliance as well as the fire of the stone.
When light enters a diamond, it actually bends or refracts. The degree to which it bends is called "the refractive index". Note: The refractive index of diamond is 2.41, the highest of any natural transparent gem.
In diamonds, the maximum angle of refraction is 24.5 degrees, called "the critical angle".
Light traveling through a diamond is reflected if it strikes a surface "outside the critical angle".
Light striking a surface "inside the critical angle", will be refracted out of a diamond.
In a well-made diamond, a high percentage of light entering through the crown starts out striking the pavilion outside the critical angle. Thus it is totally reflected to the other side of the pavilion. There it strikes outside the critical angle again, and again and is totally reflected, this time towards the crown, where it strikes within the critical angle and leaves the diamond traveling in directions in which it can be seen.
Such controlled release of light is planned leakage. If the pavilion is too deep, or too shallow, much of the light strikes inside the critical angle and leaks out the back of the stone rather than reflecting through the diamond and back through the top to the eye.
Diamonds are generally categorized into 3 main types of cuts:
- Shallow Cut A shallow cut diamond is fratter from the profile and creates the illusion of a larger stone because the bulk of its weight is desperst through out the top. The down side to this is that a diamond needs debth so that light can have somewhere to be bounced around before it heads back up to your eye. With shallow cuts that doesn't happen. Light that comes in is leaked out through the sides...not where you would like it to go, which causes a lack of brilliance and fire.
- Ideal Cut A high quality diamond that cut ideally to beautifully reflects light. This cut style is well-proportioned and carefully angled to achieve a luminous appearance.
- Deep Cut Deep cut poorly reflects light, resulting in a dull and muted appearance.
Understanding Diamond Girdle Thickness
The girdle is the outer edge of a diamond. The grade of diamonds girdle is determined by the appearance of the girdle at its thinnest point and thickest point.
A diamond's girdle can be faceted, polished smooth, or have a slightly granular appearance. Very fine cut diamonds often have faceted girdles. A diamond cutter must spend extra time to carefully facet a girdles edge.
A faceted girdle does not improve a diamonds grade. GIA grades only thickness of a diamonds girdle and not the surface appearance.
Ideal girdle thickness should range between Very Thin to Thick. Sometimes a diamond can have a perfect medium girdle around ninety-nine percent of its diameter and is only very thick at one very minute isolated point. This diamond will receive a GIA girdle grade as medium to very thick.
In this case, choosing a diamond with a very thick girdle could be acceptable because only one minute part of the girdle reached very thick and it will unlikely affect the diamonds appearance. This judgment can only be made by visual inspection by a trained Certified-Gemologist-Appraiser.
Diamonds that have grades extremely thin, very thick, or extremely thick are usually not recommended.
Now, after learning about the "CUT", a diamond's most important characteristic, you'll be able to know from our list below what makes a diamond cut: "Ideal", "Excellent", "very good", "Good", "Fair", and "Poor", and what to aim for when getting your diamond from us.