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4ct Sapphire (Radiant, 8.75×8.75mm, Blue) vs 4ct Topaz (Radiant, 9.12×9.12mm, Blue)


Quick summary: When looked from above (face-up position), 4ct Topaz (9.12×9.12mm, radiant cut) appears 9% larger than 4ct Sapphire (8.75×8.75mm, radiant cut). See below how they compare side-by-side on a ring and finger.

4ct Sapphire (radiant cut)
vs
4ct Topaz (radiant cut)
blue
 
blue
8.75×8.75 mm 9.12×9.12 mm
actual size
Actual size of 4ct Sapphire (radiant cut, 8.75×8.75mm, Blue color)   Actual size of 4ct Topaz (radiant cut, 9.12×9.12mm, Blue color)
 
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Blue 4ct Sapphire (radiant cut, 8.75×8.75mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
Blue 4ct Topaz (radiant cut, 9.12×9.12mm) 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 54%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 4ct Sapphire Radiant (8.75×8.75mm, Blue) and 4ct Topaz Radiant (9.12×9.12mm, 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 Topaz for a given carat weight, because it has higher specific gravity (4 vs. 3.53 - this means it's "heavier" compared to Topaz 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.


4 Ct Sapphire (Radiant) 4 Ct Topaz (Radiant)
8.75×8.75 mm vs 9.12×9.12 mm
72.73 mm²   79.02 mm²
Face-up size outline for 4ct Topaz (9.12×9.12mm, radiant cut)
Face-up size outline for 4ct Sapphire (8.75×8.75mm, radiant cut)
4ct Sapphire Radiant (8.75×8.75mm)
4ct Topaz Radiant (9.12×9.12mm)
Difference: 9% (6.29 mm²)
4ct Topaz (Radiant, 9.12×9.12mm) has approx. 9% more face-up area than 4ct Sapphire (Radiant, 8.75×8.75mm).


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