Diamond Cut

You may be surprised to learn that the most critical of the so-called 4 “Cs” in determining the value of a diamond (color, cut, clarity and carat) is actually cut and not carat weight. The overall appeal, symmetry and value of a diamond are largely determined by the quality of its cut.

The cut, or “make” of a diamond has a direct correlation to its value and appeal; an expert diamond cutter, such as the ones we use at Sylvia’s Antique Jewelry, can bring out a diamond’s inherent beauty with a fascinating balance of symmetry, facets, proportion and polish. In his hands, a raw stone literally comes to life. When a diamond has been well cut, it is able to both reflect and refract light. Understanding the way light moves is a critical part of the cutter’s art and over the centuries, specific facet cuts and proportions have been developed by experts to make the most of each gem and harness its particular luster. Simply put, the better the cut, the more light is directed towards the eye. An expertly cut smaller diamond may, in fact, be worth more than an over-sized “rock”. Similarly, a well cut stone will often appear larger that a diamond of the same carat weight and it will look as if it has better color and clarity. A poorly cut diamond looks dull and muted and may even be susceptible to damage. A beautifully cut diamond flashes with that bewitching, fiery brilliance that will take your breath away.

Curious to know more? Here are the different parts of a diamond.

Diameter: Width, measured from edge to edge.
Table: Largest polished facet on the top of the diamond.
Crown: The top part of a diamond extending from the table to the girdle.
Girdle: The edge where the crown and pavilion meet.
Pavilion: The bottom part of a diamond extending from the girdle down to the culet.
Depth: Total height of a diamond measured from the table to the culet.
Culet: Pointed facet at the very bottom of a polished stone.

There are specific facets for each type of diamond cut; certain types of cuts such as the emerald or Asscher cut require an exceptionally high quality stone as they have a large “table” which can highlight poor clarity or color. A round, brilliant cut, which is by far the most popular, tends to show more brilliance, whereas other cuts such as the marquise and oval shape are less expensive as their shape is not deep and are therefore generally cut from a lower carat weight stone. When a diamond is cut in proportion, it sends out that unmistakable sparkle through the top of the table. If it is too shallow a cut, the light will escape from the bottom of the stone. Similarly, if the cut is too deep, light will leak out from the side and the diamond will not have the desired flash and brilliance.
Graphic needed of shallow, deep and ideal cuts

The grade of a diamond’s cut is actually composed of three different kinds of light reflection:

1. Dispersion or Fire – Dispersion refers to the spectrum of colors that is reflected to the eye from the diamond, similar to a spectrum of colors in a rainbow. When light enters the diamond it is broken down and reflected around its interior, bouncing off its facets and then leaving through the crown of the gem. The colors stay separated and reach the eye in brilliant flashes of glorious blues, purples, reds – every color of the rainbow, in fact. This dispersion is a highly prized feature of a top quality gemstone.

2. Brilliance – This refers to the degree of whiteness or brightness of the light that exits from the stone and meets the eye.

3. Scintillation – This is the play of light you will see when a diamond moves. It is a sparkling or glittering on the diamond’s surface which represents both a reflection and refraction of light.

It is the balance of these three types of light reflection that make a true top quality diamond. The best cut diamonds have proportions that maximize their light dispersion, brilliance and scintillation and so the grading scale for cut is based upon this very delicate equation.

Diamonds are given specific grades based upon their cut:

• An Excellent cut is graded as outstanding. Only the top 1% of all diamonds meets this grade based upon their cut, polish and symmetry. This is a stone of the highest possible quality.

• An Ideal cut represents approximately the top 3% in diamond quality. This is still a rare and exquisite stone of excellent quality.

• A Very good grade puts the stone in the top 15% in diamond quality based on cut.

• A Good cut represents roughly the top 25% in terms of diamond quality based on cut. This stone is good but less expensive.

• A Fair cut represents roughly the top 35% of diamond quality based on cut. This is still a quality diamond.

• A Poor cut is the lowest of all grades. These are diamonds that have been cut too deep or too narrow and shallow so that they are leaking light from the sides or bottom. These are mediocre stones and are the least expensive.

Cut is the most important factor affecting a diamond's beauty and cost, and can also affect its durability. To decide which diamond is best for you, remember the importance of cut; choose the best grade you can afford within your given budget. Its beauty and value will stand the test of time.

Our expert consultants are available to help with advice and tips. Call us at  800-969-6930 or  Email Us