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16ct Sapphire (Round, 15.06×15.06mm, Blue) vs 31.26ct Diamond (Cushion, 18.35×18.35mm, White)


Quick summary: When looked from above (face-up position), 31.26ct Diamond (18.35×18.35mm, cushion cut) appears 70% larger than 16ct Sapphire (15.06×15.06mm, round cut). See below how they compare side-by-side on a ring and finger.

16ct Sapphire (round cut)
vs
 31.26ct Diamond (cushion cut)
blue
 
white
15.06×15.06 mm 18.35×18.35 mm
actual size
Actual size of 16ct Sapphire (round cut, 15.06×15.06mm, Blue color)   Actual size of 31.26ct Diamond (cushion cut, 18.35×18.35mm, White color)
 
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Blue 16ct Sapphire (round cut, 15.06×15.06mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
White 31.26ct Diamond (cushion cut, 18.35×18.35mm) 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
 90% vs 109%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 16ct Sapphire Round (15.06×15.06mm, Blue) and 31.26ct Diamond Cushion (18.35×18.35mm, 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.


16 Ct Sapphire (Round) 31.26 Ct Diamond (Cushion)
15.06×15.06 mm vs 18.35×18.35 mm
178.13 mm²   303.05 mm²
Face-up size outline for 31.26ct Diamond (18.35×18.35mm, cushion cut)
Face-up size outline for 16ct Sapphire (15.06×15.06mm, round cut)
16ct Sapphire Round (15.06×15.06mm)
31.26ct Diamond Cushion (18.35×18.35mm)
Difference: 70% (124.92 mm²)
31.26ct Diamond (Cushion, 18.35×18.35mm) has approx. 70% more face-up area than 16ct Sapphire (Round, 15.06×15.06mm).


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