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0.4ct Sapphire (Marquise, 7.28×3.64mm, Blue) vs 0.3ct Diamond (Round, 4.5×4.5mm, White)


Quick summary: When looked from above (face-up position), 0.4ct Sapphire (7.28×3.64mm, marquise cut) appears 18% larger than 0.3ct Diamond (4.5×4.5mm, round cut). See below how they compare side-by-side on a ring and finger.

0.4ct Sapphire (marquise cut)
vs
 0.3ct Diamond (round cut)
blue
 
white
7.28×3.64 mm 4.5×4.5 mm
actual size
Actual size of 0.4ct Sapphire (marquise cut, 7.28×3.64mm, Blue color)   Actual size of 0.3ct Diamond (round cut, 4.5×4.5mm, White color)
 
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Blue 0.4ct Sapphire (marquise cut, 7.28×3.64mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
White 0.3ct Diamond (round cut, 4.5×4.5mm) 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
 22% vs 27%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 0.4ct Sapphire Marquise (7.28×3.64mm, Blue) and 0.3ct Diamond Round (4.5×4.5mm, 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.


0.4 Ct Sapphire (Marquise) 0.3 Ct Diamond (Round)
7.28×3.64 mm vs 4.5×4.5 mm
18.81 mm²   15.9 mm²
Face-up size outline for 0.4ct Sapphire (7.28×3.64mm, marquise cut)
Face-up size outline for 0.3ct Diamond (4.5×4.5mm, round cut)
0.4ct Sapphire Marquise (7.28×3.64mm)
0.3ct Diamond Round (4.5×4.5mm)
Difference: 18% (2.91 mm²)
0.4ct Sapphire (Marquise, 7.28×3.64mm) has approx. 18% more face-up area than 0.3ct Diamond (Round, 4.5×4.5mm).


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