The term cut is sometimes confused with the shape of the diamond. However, cut refers to the facet proportions on the surface of the diamond, it's finish and symmetry. All of these greatly affect the overall appearance of the stone.
When the diamond is cut to ideal proportions, light reflects from one facet to another and then radiates through the top of the stone. This allows for fire and brilliance and makes the stone appear larger than one that is cut too deep.
If a diamond is cut too deep or too shallow, light escapes from the stone, reducing it's fire and brilliance and reducing it's value.
The cut of a diamond has three attributes :
- Brilliance — the total light reflected from a diamond
- Fire — the dispersion of light into colors of the spectrum
- Scintillation — The flashes of light, or sparkle, when a diamond is moved
- As a value factor, cut refers to a diamonds proportions, symmetry and polish.
The major components of a diamond as seen from the side are:
- Crown (top)
- Girdle (separates top from bottom)
- Pavilion (bottom v shape). A round (brilliant cut) diamond has 57 facets (or 58 if the bottom is flat and has a culet).
The large flat facet on the top is the table.
The proportions of a diamond refer to the relationships between the table size, crown angle and pavilion depth. A flat stone is referred to a shallow and a diamond with a large pavilion is referred to as deep. Theses interact with the stone's ability to interact with light.
The cut is graded as Excellent, Very Good, Good, Fair or Poor.
An understanding of diamonds cut begins with the shape of a diamond. The standard round brilliant is the shape used in most diamond jewelry. All others are known as fancy shapes.
Diamond cutting style are separated into three main categories:
- Brilliant Cut Diamond: This faceting style allows for better light reflection and is considered to have the greatest brilliance of all cutting styles.
- Step Cut Diamond: This faceting style is composed of rows of facets that resemble the steps of a staircase, examples of this are emerald cut and baguettes.
- Mixed Cut Diamond: Radiant cut diamonds have the shape of the emerald cut, but the brilliant cut.
Classic Diamond Shapes
Round Brilliant Cut Diamond
This diamond shape is the standard for all other shapes and is the most popular of all diamonds sold, and therefore usually runs about 15% higher in price.
Radiant Cut Diamond
Square or rectangle, both diamond cuts combine the elegance of the emerald cut with the brilliance of the round cut.
Oval Cut Diamond
This is an elongated round diamond and gives an illusion of length to the finger.
Princess Cut Diamond
This is a relatively new cut diamond and a variation of the radiant cut. The main differences are the corners and that this requires a deeper stone.
Marquise Cut Diamond
This diamond is elongated with pointed ends which also adds length to the hand.
Heart Shape Diamond
This is another hybrid of the oval and marquise cut diamond. Color choice is important in this shape, a higher color will be visible in it's corners.
Pear Shape Diamond
This tear drop shape diamond is a hybrid of the oval and marquise, mostly used for earrings and pendants.
Emerald Cut Diamond
This is a rectangle diamond with cut corners. It is a step cut, because it resembles stair steps. A very classic and elegant cut.
Antique Diamond Shapes
Cushion Cut Diamond
This is a mix of an old mine cut and a modern oval cut diamonds. It is rare to find a more desirable square, most are rectangle. It is very popular to set this high in a micropave mounting.
Asscher Cut Diamond
This was can be called a square emerald cut diamond. The original Asscher cut had a small table, high crown, a deep pavilion and a square culet. This is a beautiful and elegant stone in larger sizes, because the table is small, this diamond appears smaller than another cut of the same weight.
Old Mine Cut Diamond
The old mine cut was the first brilliant cut diamond, which was cushion shaped. It has a high crown, small table, deep pavilion and large culet. Because it is not very brilliant, it is usually recut to a modern round cut to maximize the diamond's brilliance.
European Cut Diamond
The old European diamond was round like the modern brilliant cut. It has a heavy crown and is very deep. It too is usually recut to the modern brilliant cut.
Rose Cut Diamond
The rose cut diamond has no crown making it very flat. It has very little fire, but is still useful in jewelry that require little height, such as diamond by the yard. Because the top of the diamond is flat, it appears large, giving a lot of flash for little cash.
Briolette cut diamonds are found in jewels from the Victorian, Edwardian and Art Deco Eras. It is a drop shape stone with facets all the way around. There is no pavilion, table or crown. It looks a little bit like a diamond pineapple.
Side Stone Diamond Shapes
Trapezoid Shape Diamond
This unusual cut is used to accentuates the center diamond. The trapezoid has the same step cut as the emerald cut so it is a beautiful side stone for any step cut diamond.
Half Moon Shape Diamond
The half moon looks like a round or oval so it really highlights these shapes. It also looks great with a radiant cut diamond.
Trillion and Triangle Shape Diamond
There are variations of these diamonds. The trillion has rounded sides while the triangle has straight sides. These make great side stones for a solitaire.
Baguette and Tapered Baguette Diamonds
Theses are step cut diamonds used frequently as side stones, although it doesn't have the sparkle of a brilliant cut, it has a classic understated beauty.
Single cut Diamonds
The single cut diamond is used to accent jewelry, It has only 8 facets so it is less brilliant than a regular 58 facet round, but the price per carat is much less.