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3.1ct Sapphire (Emerald, 9.11×6.26mm, Light Blue) vs 4ct Diamond (Cushion, 9.25×9.25mm, White)


Quick summary: When looked from above (face-up position), 4ct Diamond (9.25×9.25mm, cushion cut) appears 45% larger than 3.1ct Sapphire (9.11×6.26mm, emerald cut). See below how they compare side-by-side on a ring and finger.

3.1ct Sapphire (emerald cut)
vs
 4ct Diamond (cushion cut)
light blue
 
white
9.11×6.26 mm 9.25×9.25 mm
actual size
Actual size of 3.1ct Sapphire (emerald cut, 9.11×6.26mm, Light Blue color)   Actual size of 4ct Diamond (cushion cut, 9.25×9.25mm, White color)
 
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Light Blue 3.1ct Sapphire (emerald cut, 9.11×6.26mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
White 4ct Diamond (cushion cut, 9.25×9.25mm) on a right ring and finger
Your settings
Ring
 Gold
Skin tone
 Light
Ring diameter
 16.9 mm
Ring width
 3.0 mm
Finger length
 64 mm
Finger coverage
 38% vs 55%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 3.1ct Sapphire Emerald (9.11×6.26mm, Light Blue) and 4ct Diamond Cushion (9.25×9.25mm, White) as they would appear on a ring and finger. Adjust the ring and finger size to get an idea of how these gemstones would look on your finger.

Where to buy?

For certified gemstones, high-end gemstone jewelry, and birthstone jewelry, see Blue Nile

Face-up Size

All things being equal, Sapphire will face-up smaller than Diamond for a given carat weight, because it has higher specific gravity (4 vs. 3.52 - this means it's "heavier" compared to Diamond of the same size). Face-up size also depends heavily on the proportions of the cut.

Face-up area is a measure of the size of the gem when viewed from above (as set in a ring). It tells you how big the gem is at the girdle plane.


3.1 Ct Sapphire (Emerald) 4 Ct Diamond (Cushion)
9.11×6.26 mm vs 9.25×9.25 mm
53.04 mm²   77.01 mm²
Face-up size outline for 4ct Diamond (9.25×9.25mm, cushion cut)
Face-up size outline for 3.1ct Sapphire (9.11×6.26mm, emerald cut)
3.1ct Sapphire Emerald (9.11×6.26mm)
4ct Diamond Cushion (9.25×9.25mm)
Difference: 45% (23.97 mm²)
4ct Diamond (Cushion, 9.25×9.25mm) has approx. 45% more face-up area than 3.1ct Sapphire (Emerald, 9.11×6.26mm).


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