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4ct Ruby (Round, 9.49×9.49mm, Red) vs 2.75ct Diamond (Round, 9.11×9.11mm, White)


Quick summary: When looked from above (face-up position), 4ct Ruby (9.49×9.49mm, round cut) appears 9% larger than 2.75ct Diamond (9.11×9.11mm, round cut). See below how they compare side-by-side on a ring and finger.

4ct Ruby (round cut)
vs
 2.75ct Diamond (round cut)
red
 
white
9.49×9.49 mm 9.11×9.11 mm
actual size
Actual size of 4ct Ruby (round cut, 9.49×9.49mm, Red color)   Actual size of 2.75ct Diamond (round cut, 9.11×9.11mm, White color)
 
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Red 4ct Ruby (round cut, 9.49×9.49mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
White 2.75ct Diamond (round cut, 9.11×9.11mm) 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
 57% vs 54%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 4ct Ruby Round (9.49×9.49mm, Red) and 2.75ct Diamond Round (9.11×9.11mm, 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, Ruby 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.


4 Ct Ruby (Round) 2.75 Ct Diamond (Round)
9.49×9.49 mm vs 9.11×9.11 mm
70.73 mm²   65.18 mm²
Face-up size outline for 4ct Ruby (9.49×9.49mm, round cut)
Face-up size outline for 2.75ct Diamond (9.11×9.11mm, round cut)
4ct Ruby Round (9.49×9.49mm)
2.75ct Diamond Round (9.11×9.11mm)
Difference: 9% (5.55 mm²)
4ct Ruby (Round, 9.49×9.49mm) has approx. 9% more face-up area than 2.75ct Diamond (Round, 9.11×9.11mm).


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