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18ct Diamond (Oval, 21.27×14.18mm, White) vs 18ct Sapphire (Oval, 19.82×13.21mm, Blue)


Quick summary: When looked from above (face-up position), 18ct Diamond (21.27×14.18mm, oval cut) appears 15% larger than 18ct Sapphire (19.82×13.21mm, oval cut). See below how they compare side-by-side on a ring and finger.

18ct Diamond (oval cut)
vs
 18ct Sapphire (oval cut)
white
 
blue
21.27×14.18 mm 19.82×13.21 mm
actual size
Actual size of 18ct Diamond (oval cut, 21.27×14.18mm, White color)   Actual size of 18ct Sapphire (oval cut, 19.82×13.21mm, Blue color)
 
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
White 18ct Diamond (oval cut, 21.27×14.18mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
Blue 18ct Sapphire (oval cut, 19.82×13.21mm) 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
 84% vs 79%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 18ct Diamond Oval (21.27×14.18mm, White) and 18ct Sapphire Oval (19.82×13.21mm, 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.


18 Ct Diamond (Oval) 18 Ct Sapphire (Oval)
21.27×14.18 mm vs 19.82×13.21 mm
247.32 mm²   214.69 mm²
Face-up size outline for 18ct Diamond (21.27×14.18mm, oval cut)
Face-up size outline for 18ct Sapphire (19.82×13.21mm, oval cut)
18ct Diamond Oval (21.27×14.18mm)
18ct Sapphire Oval (19.82×13.21mm)
Difference: 15% (32.63 mm²)
18ct Diamond (Oval, 21.27×14.18mm) has approx. 15% more face-up area than 18ct Sapphire (Oval, 19.82×13.21mm).


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