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3.1ct Diamond (Round, 9.48×9.48mm, White) vs 3.5ct Sapphire (Round, 9.08×9.08mm, Blue)


Quick summary: When looked from above (face-up position), 3.1ct Diamond (9.48×9.48mm, round cut) appears 9% larger than 3.5ct Sapphire (9.08×9.08mm, round cut). See below how they compare side-by-side on a ring and finger.

3.1ct Diamond (round cut)
vs
 3.5ct Sapphire (round cut)
white
 
blue
9.48×9.48 mm 9.08×9.08 mm
actual size
Actual size of 3.1ct Diamond (round cut, 9.48×9.48mm, White color)   Actual size of 3.5ct Sapphire (round cut, 9.08×9.08mm, Blue color)
 
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
White 3.1ct Diamond (round cut, 9.48×9.48mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
Blue 3.5ct Sapphire (round cut, 9.08×9.08mm) 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 3.1ct Diamond Round (9.48×9.48mm, White) and 3.5ct Sapphire Round (9.08×9.08mm, Blue) 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 Diamond (Round) 3.5 Ct Sapphire (Round)
9.48×9.48 mm vs 9.08×9.08 mm
70.58 mm²   64.75 mm²
Face-up size outline for 3.1ct Diamond (9.48×9.48mm, round cut)
Face-up size outline for 3.5ct Sapphire (9.08×9.08mm, round cut)
3.1ct Diamond Round (9.48×9.48mm)
3.5ct Sapphire Round (9.08×9.08mm)
Difference: 9% (5.83 mm²)
3.1ct Diamond (Round, 9.48×9.48mm) has approx. 9% more face-up area than 3.5ct Sapphire (Round, 9.08×9.08mm).


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