3 Carat Cushion (9×9×5.2mm) vs. 2.5 Carat Cushion (8.5×8.5×4.9mm)

Diamond comparison

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Actual size of 3ct Cushion diamond
Actual size
sample image
vs.
Actual size of 2.5ct Cushion diamond
Actual size
sample image
3 ct Cushion (9×9×5.2mm) 2.5 ct Cushion (8.5×8.5×4.9mm)
Cutting style
(modified) brilliant
(modified) brilliant
Weight
3 ct
2.5 ct
Measurements
9×9×5.2 mm
8.5×8.5×4.9 mm
Total depth
57.8% too shallow!
57.6% too shallow!
L/W ratio
1
1
Face-up size
Borderline
Inadequate
 
This diamond is borderline SPREAD CUT!
This diamond is a SPREAD CUT!
Actual diamond size
Actual diamond size
Before purchasing a diamond, one should make sure it looks its weight. It's important to understand that carat weight does not equal face-up size.

Two diamonds of exactly the same weight (and shape) can vary quite considerably in face-up size. This depends on the proportions of the cut (e.g., deep cuts will face up smaller).

Here you can see the actual sizes of 3ct Cushion (9×9×5.2mm) and 2.5ct Cushion (8.5×8.5×4.9mm) as they would appear on a ring and finger.

Adjust the ring and finger size to get an idea of how these stones would look on your finger. To choose different diamonds or to change diamond parameters click here.

Compare prices and availability from recommended online vendors:


Settings
Ring: Skin tone:
Ring width: 3.0 mm
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Left finger image
Ring on a left finger
3ct Cushion on a left ring
64 mm
Right finger image
Ring on a right finger
2.5ct Cushion on a right ring
Your settings
Ring
Gold
Skin tone
Light
Ring diameter
16.9 mm
Ring width
3.0 mm
Finger length
64 mm
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Ring diameter: 16.9 mm
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3ct Cushion side view Side view of ring
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2.5ct Cushion side view Side view of ring
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Face-up area
72.9 mm²  (±5%)
65.03 mm²  (±5%)
Face-up area is a measure of the size of the diamond when viewed from the top (as set in a ring).

It tells you how big the diamond is at the girdle plane. It's important for a diamond to have sufficient face-up size for its carat weight.
Face-up size outline
Face-up size outline
3ct Cushion (9×9×5.2mm)
2.5ct Cushion (8.5×8.5×4.9mm)
Difference: 7.87mm² (12%)
3 carat Cushion (9×9×5.2mm) has approx. 12% more top surface area than 2.5 carat Cushion (8.5×8.5×4.9mm).
Face-up area per carat
24.3 mm²/ct
26.01 mm²/ct
To learn about the accuracy of these numbers, click here.

Quick Buying Guide

3ct Cushion (9×9×5.2mm)
2.5ct Cushion (8.5×8.5×4.9mm)
Min. clarity
SI1 or better
SI1 or better
Min. color (platinum solitaire)
H+
H+
Depth percentage
59 - 70%
59 - 70%
Table percentage
56 - 70%
56 - 70%
Length-to-width ratio
1.00 - 1.35
1.00 - 1.35
Min. polish/symmetry
Good or better
Good or better
 Detailed buying guide

Additional Info

3ct Cushion (9×9×5.2mm)
2.5ct Cushion (8.5×8.5×4.9mm)
Face-up size
A bit large for 3 carat Cushion
Too large for 2.5 carat Cushion
Facets
usually 58
usually 58
Length
9 mm
8.5 mm
Width
9 mm
8.5 mm
Depth
5.2 mm
4.9 mm
Gram weight
0.6 g (0.0212 ounces)
0.5 g (0.0176 ounces)
Points
300 pts
250 pts
Volume
170.45 mm³
142.05 mm³


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Depth percentage for 3 carat Cushion (9×9×5.2mm)

Depth percentage of Cushion cut is the ratio of the total depth (measured from table to culet) to its width. The total depth percentage of this diamond is 57.8%, which is too shallow!. (Recommended depth percentage for Cushions is between 59% and 70%)

Depth percentage for cushions is calculated with the following formula:
Depth % = (total depth ÷ width) × 100

3 carat Cushion (9×9×5.2mm) depth %:
Total depth: 5.2 mm
Width = 9 mm
Depth % = (5.2 ÷ 9 ) × 100 = 57.8%

Depth percentage for 2.5 carat Cushion (8.5×8.5×4.9mm)

Depth percentage of Cushion cut is the ratio of the total depth (measured from table to culet) to its width. The total depth percentage of this diamond is 57.6%, which is too shallow!. (Recommended depth percentage for Cushions is between 59% and 70%)

Depth percentage for cushions is calculated with the following formula:
Depth % = (total depth ÷ width) × 100

2.5 carat Cushion (8.5×8.5×4.9mm) depth %:
Total depth: 4.9 mm
Width = 8.5 mm
Depth % = (4.9 ÷ 8.5 ) × 100 = 57.6%

About Depth Percentage
Depth percentage is one of the most important measurements as it plays a critical role in diamond's appearance. If a diamond is cut too deep or too shallow, light leaks out, making the stone less brilliant and fiery. Deep cuts also add hidden weight.

Diamonds that fall out of recommended depth range are generally less desirable and usually best to be avoided.


Face-up size evaluation for 3 carat Cushion (9×9×5.2mm)

The face-up size of this 3 carat Cushion (9×9×5.2mm) is slightly out of normal range for 3ct diamonds of this shape. Compared to 3 carat Cushion reference diamond, this diamond seems a bit too large when viewed from the top. This could be indicative of a spread cut, which is not a good sign.

A spread cut is a diamond that is cut to maximize spread. It looks larger than a well-cut 3ct Cushion when viewed from the top, however, this is usually not a good thing. Spread cuts are typically too shallow, which allows light to leak out of the stone instead of being properly returned back to the viewer's eye.

Spread cuts can look lifeless and flat, and can sometimes exhibit a fish-eye effect. They may also come with an extremely thin girdle which can easily chip.

The bottom line: This diamond could be a spread cut. Caution is advised, since spread cuts usually lack the sparkle and perfection that is expected of a beautiful diamond.

3 carat Cushion reference diamond

Since there are no specific ideal proportions defined for Cushion cuts, an estimation formula is used to calculate the Cushion reference diamond.
Parameters:
Weight: 3ct
Depth: 64%
L/W ratio: 1
 
Calculated values:
Length: 8.4 mm
Width: 8.4 mm
Depth: 5.38 mm
*Est. face-up area: 63.5 mm²
Note: Cushion diamonds with face-up area of within 9% lower and 12% higher than reference Cushion diamond area are considered to be of adequate face-up size.
* Estimated Face-up area: Face-up area of Cushion cuts is only an estimation (±5%). Due to uniqueness of each stone, it's impossible to accurately calculate face-up area given only a diamond's measurements.
To learn more about diamond size evaluation, click here.


Face-up size evaluation for 2.5 carat Cushion (8.5×8.5×4.9mm)

The face-up size of this 2.5 carat Cushion (8.5×8.5×4.9mm) is out of normal range for 2.5ct diamonds of this shape. Compared to 2.5 carat Cushion reference diamond, this diamond appears too big when viewed from the top. You might think that's a good thing, however, it's not. This is a so called spread cut.

A spread cut is a diamond that is cut to maximize spread. It looks larger than a well-cut 2.5ct Cushion when viewed from the top, however, this is not a good thing. Spread cuts are typically too shallow, which allows light to leak out of the stone instead of being properly returned back to the viewer's eye.

Spread cuts usually look lifeless and flat, and can sometimes exhibit a fish-eye effect. They may also come with an extremely thin girdle which can easily chip.

The bottom line: Spread cuts generally lack the brilliance and perfection that is expected of a beautiful diamond. Don't be fooled into thinking that you're getting a larger diamond for the money. This could be a rather flat, boring stone.

2.5 carat Cushion reference diamond

Since there are no specific ideal proportions defined for Cushion cuts, an estimation formula is used to calculate the Cushion reference diamond.
Parameters:
Weight: 2.5ct
Depth: 64%
L/W ratio: 1
 
Calculated values:
Length: 7.91 mm
Width: 7.91 mm
Depth: 5.06 mm
*Est. face-up area: 56.31 mm²
Note: Cushion diamonds with face-up area of within 9% lower and 12% higher than reference Cushion diamond area are considered to be of adequate face-up size.
* Estimated Face-up area: Face-up area of Cushion cuts is only an estimation (±5%). Due to uniqueness of each stone, it's impossible to accurately calculate face-up area given only a diamond's measurements.
To learn more about diamond size evaluation, click here.


Face-up Area per Carat

Face-up area per carat is calculated by dividing face-up area of the diamond with its carat weight. It tells you how many square millimeters of the top surface area a diamond is showing or would show for 1 carat weight. This can be useful when comparing stones of similar weights as it tells you how much spread per carat you will get.

Note: Face-up size does not linearly grow with carat weight, which means the heavier the stone, the smaller its face-up area per carat (e.g., 1ct stone will have higher face-up area per carat than 2ct stone).

Face-up area per carat for 3ct Cushion (9×9×5.2mm):
Top surface area = 72.9 mm²
Weight = 3ct

Face-up area per carat = 72.9 ÷ 3 = 24.3mm²/ct

Face-up area per carat for 2.5ct Cushion (8.5×8.5×4.9mm):
Top surface area = 65.03 mm²
Weight = 2.5ct

Face-up area per carat = 65.03 ÷ 2.5 = 26.01mm²/ct

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