A diamond's cut also referred to as the stone's “make,” is the proportions of its facets and its overall finish. Cut is a result of a craftsman's skill in transforming a rough crystal into a magnificent gem. A well-proportioned (well-cut) stone will create that fire and sparkle of flashing rainbow colors and liveliness.
The stone must be cut at exactly the right angles relative to one another to truly maximize the reflection of light. The table size (flat surface on the top) and pavilion depth (bottom half of the stone) have the greatest effect on how light travels within the diamond.
As you can see, a well-cut diamond does a more effective job in reflecting light out the top of the stone to your eye. Light enters through the table and travels to the pavilion reflecting at the correct angles from facet to facet, and then exits back out the top of diamond through the table and to the observer’s eye. This burst of light is the brilliance and sparkle we mentioned and it is what makes diamonds so beautiful.
In a poorly cut diamond (too deep or too shallow) light will enter through the table travel to the pavilion, reflect at a wrong angle and then leak out the sides or bottom of the stone rather then back out the table to the eye. Less light reflected back to the eye means less brilliance and causes the diamond to appear dull and lifeless Keep in mind that Cut does not mean Shape. Shape is a matter of individual preference.
Below is a diagram of the basic parts of a diamond:
Proportions Create Brilliance – What are good proportions?
Proportions are the size and angle relationships between the facets and different parts of the stone. Gemologists have turned this into a science – they have discovered that the best-cut diamonds will have proportions that follow set formulae. Stones that adhere to these precise formulae will exhibit the most brilliance – while there are many measurements involved in judging the Cut grade, the most important proportions to consider is the depth compared to the diameter, and the diameter of the table compared to the diameter of the diamond. The more successful the cutter is in balancing these proportions, the better the cut and the more valuable the stone will be.
Finish creates the Sparkle – What is a good Finish?
The “Finish” of a stone is another important factor of the diamond's cut. The finish refers to the polish and symmetry of the diamond. The polish grade of a diamond describes the overall condition or smoothness of the diamond's surface, and the symmetry grade describes the shape, placement and alignment of the facets. With poor symmetry the facets may have sever external imbalances that can misdirect light as it travels within the stone. The polish of a diamond, while not as important as the symmetry, a poor polish grade may cause the facets to appear dulled or blurred. For your convenience we have clearly listed the polish and symmetry grades in the detail's page of each diamond. The grades can also be found within the stone's grading report. For diamonds that exhibit the most sparkle, look for a symmetry grade of excellent (EX), very good (VG), or good (G) in a GIA grading report, and ideal (ID), excellent (EX), very good (VG), good (G) for an AGSL or EGL grading report. Try and avoid diamonds with symmetry grades of poor (P) or fair (F), which severely compromises the stone's beauty.
Which Cut is right for me?
DreamStone’s Signature Ideal Cut: This is our signature line of our most brilliant cut diamonds. Approximately 1% of diamonds earn this grade – The highest grades of cut proportions to achieve maximum brilliance and fire and an equally highest quality grade of polish and symmetry for ultimate sparkle and life. Perfect for those who want to know they have the best that money can buy. This category applies to round diamonds only.
Ideal Cut: These diamonds reflect nearly all the light that enters them. In a GIA grading report this cut is called Excellent, while other grading reports call it an Ideal Cut. Whichever one of these names is coined, you can rest assured that this stone is cut to maximize brilliance and sparkle. The cut grade applies to round diamonds only.
Very Good Cut: These diamonds effectively reflect most of the light that enters them. This cut grade shares many of the Ideal and Excellent grade proportions while other variables such as the, girdle width or table size, may have been cut to create a slightly larger stone. The price of these diamonds may be found below the Ideal or Excellent cuts.
Good Cut: These diamonds do a good job in reflecting much of the light that enters them. The cutter has decided to create a larger gem out of the original rough diamond, while still keeping within acceptable industry proportions. A good cut stone is less expensive than very good cuts, and can be a great choice for those that want to balance quality, size and budget.
Fair Cut: While still a quality diamond, these stones have been cut to create the largest possible gem out of the original rough diamond, which compromised some preferred proportions. A fair cut is much more affordable then a good cut, but not as brilliant.
Poor Cut: Stones that fall under these proportions will reflect a very small amount of light that enters them and were cut mostly for size with few other considerations. We do not recommend these stones, and DreamStone will not carry them to ensure the highest quality of diamonds and fine jewelry for our customers.
The cut of a stone represents its quality and craftsmanship. It is therefore, important to remember that it is quality that is more important than carat size. A well-cut stone such as Ideal/Excellent, Very Good, or Good will bring out a diamond's life and personality, the very essence of what makes them so beautiful.
The table below will give you a guideline of the proportions behind each of the preferred cut grades: