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3ct Sapphire (Round, 8.62×8.62mm, Blue) vs 0.4ct Diamond (Round, 4.79×4.79mm, White)


Quick summary: When looked from above (face-up position), 3ct Sapphire (8.62×8.62mm, round cut) appears 3.2 times larger than 0.4ct Diamond (4.79×4.79mm, round cut). See below how they compare side-by-side on a ring and finger.

3ct Sapphire (round cut)
vs
 0.4ct Diamond (round cut)
blue
 
white
8.62×8.62 mm 4.79×4.79 mm
actual size
Actual size of 3ct Sapphire (round cut, 8.62×8.62mm, Blue color)   Actual size of 0.4ct Diamond (round cut, 4.79×4.79mm, White color)
 
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Blue 3ct Sapphire (round cut, 8.62×8.62mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
White 0.4ct Diamond (round cut, 4.79×4.79mm) 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
 52% vs 29%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 3ct Sapphire Round (8.62×8.62mm, Blue) and 0.4ct Diamond Round (4.79×4.79mm, 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 Sapphire (Round) 0.4 Ct Diamond (Round)
8.62×8.62 mm vs 4.79×4.79 mm
58.36 mm²   18.02 mm²
Face-up size outline for 3ct Sapphire (8.62×8.62mm, round cut)
Face-up size outline for 0.4ct Diamond (4.79×4.79mm, round cut)
3ct Sapphire Round (8.62×8.62mm)
0.4ct Diamond Round (4.79×4.79mm)
Difference: 224% (40.34 mm²)
3ct Sapphire (Round, 8.62×8.62mm) has approx. 224% more face-up area than 0.4ct Diamond (Round, 4.79×4.79mm). In other words, it's 3.24x larger.


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