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3.5ct Spinel (Radiant, 8.66×8.66mm, Red) vs 3.5ct Alexandrite (Radiant, 8.56×8.56mm, Bluish Green)


Quick summary: When looked from above (face-up position), 3.5ct Spinel (8.66×8.66mm, radiant cut) appears 2% larger than 3.5ct Alexandrite (8.56×8.56mm, radiant cut). See below how they compare side-by-side on a ring and finger.

3.5ct Spinel (radiant cut)
vs
3.5ct Alexandrite (radiant cut)
red
 
bluish green
8.66×8.66 mm 8.56×8.56 mm
actual size
Actual size of 3.5ct Spinel (radiant cut, 8.66×8.66mm, Red color)   Actual size of 3.5ct Alexandrite (radiant cut, 8.56×8.56mm, Bluish Green color)
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Red 3.5ct Spinel (radiant cut, 8.66×8.66mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
Bluish Green 3.5ct Alexandrite (radiant cut, 8.56×8.56mm) 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 51%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 3.5ct Spinel Radiant (8.66×8.66mm, Red) and 3.5ct Alexandrite Radiant (8.56×8.56mm, Bluish Green) 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, Alexandrite will face-up smaller than Spinel for a given carat weight, because it has higher specific gravity (3.73 vs. 3.6 - this means it's "heavier" compared to Spinel 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.


3.5 Ct Spinel (Radiant) 3.5 Ct Alexandrite (Radiant)
8.66×8.66 mm vs 8.56×8.56 mm
71.25 mm²   69.61 mm²
Face-up size outline for 3.5ct Spinel (8.66×8.66mm, radiant cut)
Face-up size outline for 3.5ct Alexandrite (8.56×8.56mm, radiant cut)
3.5ct Spinel Radiant (8.66×8.66mm)
3.5ct Alexandrite Radiant (8.56×8.56mm)
Difference: 2% (1.64 mm²)
3.5ct Spinel (Radiant, 8.66×8.66mm) has approx. 2% more face-up area than 3.5ct Alexandrite (Radiant, 8.56×8.56mm).


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