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4.5ct Sapphire (Round, 9.87×9.87mm, Blue) vs 4.5ct Diamond (Round, 10.73×10.73mm, White)


Quick summary: When looked from above (face-up position), 4.5ct Diamond (10.73×10.73mm, round cut) appears 18% larger than 4.5ct Sapphire (9.87×9.87mm, round cut). See below how they compare side-by-side on a ring and finger.

4.5ct Sapphire (round cut)
vs
 4.5ct Diamond (round cut)
blue
 
white
9.87×9.87 mm 10.73×10.73 mm
actual size
Actual size of 4.5ct Sapphire (round cut, 9.87×9.87mm, Blue color)   Actual size of 4.5ct Diamond (round cut, 10.73×10.73mm, White color)
 
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Blue 4.5ct Sapphire (round cut, 9.87×9.87mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
White 4.5ct Diamond (round cut, 10.73×10.73mm) 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 64%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 4.5ct Sapphire Round (9.87×9.87mm, Blue) and 4.5ct Diamond Round (10.73×10.73mm, 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.


4.5 Ct Sapphire (Round) 4.5 Ct Diamond (Round)
9.87×9.87 mm vs 10.73×10.73 mm
76.51 mm²   90.43 mm²
Face-up size outline for 4.5ct Diamond (10.73×10.73mm, round cut)
Face-up size outline for 4.5ct Sapphire (9.87×9.87mm, round cut)
4.5ct Sapphire Round (9.87×9.87mm)
4.5ct Diamond Round (10.73×10.73mm)
Difference: 18% (13.92 mm²)
4.5ct Diamond (Round, 10.73×10.73mm) has approx. 18% more face-up area than 4.5ct Sapphire (Round, 9.87×9.87mm).


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