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3ct Diamond (Oval, 10×8mm, White) vs 4ct Sapphire (Oval, 12×8mm, White)


Quick summary: When looked from above (face-up position), 4ct Sapphire (12×8mm, oval cut) appears 20% larger than 3ct Diamond (10×8mm, oval cut). See below how they compare side-by-side on a ring and finger.

3ct Diamond (oval cut)
vs
 4ct Sapphire (oval cut)
white
 
white
10×8 mm 12×8 mm
actual size
Actual size of 3ct Diamond (oval cut, 10×8mm, White color)   Actual size of 4ct Sapphire (oval cut, 12×8mm, White color)
 
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
White 3ct Diamond (oval cut, 10×8mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
White 4ct Sapphire (oval cut, 12×8mm) 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
 48% vs 48%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 3ct Diamond Oval (10×8mm, White) and 4ct Sapphire Oval (12×8mm, 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.


3 Ct Diamond (Oval) 4 Ct Sapphire (Oval)
10×8 mm vs 12×8 mm
65.6 mm²   78.72 mm²
Face-up size outline for 4ct Sapphire (12×8mm, oval cut)
Face-up size outline for 3ct Diamond (10×8mm, oval cut)
3ct Diamond Oval (10×8mm)
4ct Sapphire Oval (12×8mm)
Difference: 20% (13.12 mm²)
4ct Sapphire (Oval, 12×8mm) has approx. 20% more face-up area than 3ct Diamond (Oval, 10×8mm).


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