The cushion is a classic diamond cut that has been around for almost 200 years. Being the most popular diamond shape for the first century of its existence, the cushion cut used to be the de facto diamond shape until the early 20th century. If you are interested in buying a diamond with an elegant and soft design, our cushion cut diamond guide is a must-read.
History of Cushion Cut Diamonds
Although the cushion cut may seem to have a contemporary design, its history traces back to the 19th century.
At the time a diamond with square shape and rounded corners was referred to as “mine cut” after Brazillian diamond mines. Later the mine cut became known as the “old mines” after diamonds were discovered in South Africa as well.
Being the most popular cut in the 19th century, the cushion cut was not limited to diamonds, most gemstones were cut into this shape.
Some experts believe that the modern cushion cut was not inspired by only the old mine cut. Such cuts as the table, Peruzzi and candlelight also have a great influence on the modern cushion cut.
The cushion cut, usually featuring 58 facets, has been modified over time thanks to the evolution of diamond cutting and the cleaving process.
The modern cushion cut is a combination of the classic old mine and the round brilliant facet patterns. As the name suggests, this cut usually has a soft square or rectangular shape with curved corners.
Today cushion cut diamonds are one of the most popular choices among modern brides-to-be.
Cushion Cut Diamond Cut Quality Guide
Cushion cut standards vary more than any other shape, which is why cut parameters are very loose. With soft-sided fancy shapes, it’s important to understand that your choice should be dictated by your personal preferences.
The GIA (Gemological Institute of America) doesn’t provide cut grading for cushion cut diamonds due to their complex and unique structure. However, there are still some key features to be considered when choosing a cushion diamond.
Although cushion cut diamonds have less brilliance than round cut diamonds, they often have a better fire, which makes them so attractive for buyers. To choose the best stone you need to pay special attention to the symmetry and polish grades listed in the certificate. Excellent or very good symmetry and polish are strongly recommended.
The facets on the right and left halves of the stone should have the same shape and size. All the points of the facets should meet, there should not be missing or extra ones. The more symmetrical the facets, the more beautiful the stone.
The chart below will serve you as a general guideline in evaluating the cut quality of cushion cut diamonds.
| EXCELLENT | VERY GOOD | GOOD | FAIR | POOR | |
|---|---|---|---|---|---|
| TABLE % | 61 - 67 | 58 - 60 or 68 - 70 | 56 - 57 or 71 | 54 - 55 or 72 - 73 | < 54 or > 73 |
| DEPTH % | 61 - 67 | 58 - 60.9 or 67.1 - 70 | 56 - 57.9 or 70.1 - 71 | 54 - 55.9 or 71.1 - 73 | < 54 or > 73 |
| GIRDLE | Very Thin to Slightly Thick | Very Thin to Slightly Thick | Very Thin to Thick | Very Thin to Very Thick | Extremely Thin to Extremely Thick |
| CULET | None | Very Small | Small | Medium | > Medium |
Cushion Cut Diamond Colour Guide
The colour of cushion cut diamonds is graded on a scale from D to Z, where D signifies a completely colourless stone and Z means an easily noticeable yellow or brown tint.
Being one of the most popular diamond cuts, the cushion is not the best shape to mask colour and tints. For this reason, it is recommended to opt for H or better colour if the stone is going to be set in platinum or white gold. In the case of yellow or rose gold, you may buy a diamond in J or even K colour.
Of course H colour falls in the “near colourless” range but it has a very slight yellow tint which is really hard to notice, especially if the stone is set into yellow or rose gold as coloured metals tend to mask the tints.
The chart below provides a general guide for evaluating colour in cushion cut diamonds.
| SIZE | EXCELLENT | VERY GOOD | GOOD | FAIR | POOR |
|---|---|---|---|---|---|
| < .50 ct. | D - G | H - I | J - K | L - M | > M |
| .51-1.0 ct. | D - F | G | H - I | J - K | > K |
| 1.0-2.0 ct. | D - F | D - F | G - H | I - J | > J |
| > 2.0 ct. | D - F | D - F | G | H - I | > I |
Cushion Cut Diamond Clarity Guide
The GIA grades clarity of cushion cut diamonds on a scale from FL to I3, where FL means a flawless stone and I3 indicates a heavily included diamond.
To have an eye-clean diamond it is best to opt for a stone in the SI clarity range. However, since the cushion cut has a large open table, it can be difficult to find an eye-clean diamond in SI2 grade, meaning you might need extra efforts to find a good stone. Additionally, try to find a diamond in which inclusions are in the corners. These flaws are less noticeable, especially if they are covered by prongs.
The clarity chart below provides a general guide for evaluating clarity in cushion cut diamonds.
| SIZE | EXCELLENT | VERY GOOD | GOOD | FAIR | POOR |
|---|---|---|---|---|---|
| < .50 ct. | FL - VS2 | SI1 - SI2 | I1 | I2 | > I2 |
| .51-1.0 ct. | FL - VS1 | VS2 - SI1 | SI2 | I1 - I2 | > I2 |
| 1.0-2.0 ct. | FL - VVS2 | VS1 - VS2 | SI1 - SI2 | I1 | > I1 |
| > 2.0 ct. | FL - VVS2 | VS1 - VS2 | SI1 | SI2 | > SI2 |
Cushion Cut Diamond Length to Width Ratio
The length to width ratio expresses how relatively long or wide a diamond appears. It is calculated by dividing the length of the diamond by its width.
Each fancy diamond shape has a certain length to width ratio that is considered most appealing for that shape. Classic cushion cut diamonds come in a square shape with a length to width ratio of 1.00. However, they often can be found in slightly rectangular shapes with a length to width ratio of 1.10-1.20.
The chart below serves as a guideline for evaluating the ratio of cushion cut diamonds.
| EXCELLENT | VERY GOOD | GOOD | FAIR | POOR | |
|---|---|---|---|---|---|
| SQUARE | 1.00 - 1.03 | 1.00 - 1.03 | 1.04 - 1.05 | 1.06 - 1.08 | > 1.08 |
| RECTANGLE | 1.15 - 1.20 | 1.10 - 1.14 or 1.21 - 1.30 | 1.10 - 1.14 or 1.21 - 1.30 | 1.08 - 1.09 or 1.31 - 1.50 | < 1.08 or > 1.50 |
