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3.5ct Diamond (Round, 9.87×9.87mm, White) vs 3.1ct Ruby (Round, 8.72×8.72mm, Red)


Quick summary: When looked from above (face-up position), 3.5ct Diamond (9.87×9.87mm, round cut) appears 28% larger than 3.1ct Ruby (8.72×8.72mm, round cut). See below how they compare side-by-side on a ring and finger.

3.5ct Diamond (round cut)
vs
 3.1ct Ruby (round cut)
white
 
red
9.87×9.87 mm 8.72×8.72 mm
actual size
Actual size of 3.5ct Diamond (round cut, 9.87×9.87mm, White color)   Actual size of 3.1ct Ruby (round cut, 8.72×8.72mm, Red color)
 
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
White 3.5ct Diamond (round cut, 9.87×9.87mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
Red 3.1ct Ruby (round cut, 8.72×8.72mm) 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
 59% vs 52%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 3.5ct Diamond Round (9.87×9.87mm, White) and 3.1ct Ruby Round (8.72×8.72mm, Red) 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.


3.5 Ct Diamond (Round) 3.1 Ct Ruby (Round)
9.87×9.87 mm vs 8.72×8.72 mm
76.51 mm²   59.72 mm²
Face-up size outline for 3.5ct Diamond (9.87×9.87mm, round cut)
Face-up size outline for 3.1ct Ruby (8.72×8.72mm, round cut)
3.5ct Diamond Round (9.87×9.87mm)
3.1ct Ruby Round (8.72×8.72mm)
Difference: 28% (16.79 mm²)
3.5ct Diamond (Round, 9.87×9.87mm) has approx. 28% more face-up area than 3.1ct Ruby (Round, 8.72×8.72mm).


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