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8.5ct Spinel (Marquise, 20.56×10.28mm, Red) vs 8.5ct Alexandrite (Marquise, 20.32×10.16mm, Bluish Green)


Quick summary: When looked from above (face-up position), 8.5ct Spinel (20.56×10.28mm, marquise cut) appears 2% larger than 8.5ct Alexandrite (20.32×10.16mm, marquise cut). See below how they compare side-by-side on a ring and finger.

8.5ct Spinel (marquise cut)
vs
 8.5ct Alexandrite (marquise cut)
red
 
bluish green
20.56×10.28 mm 20.32×10.16 mm
actual size
Actual size of 8.5ct Spinel (marquise cut, 20.56×10.28mm, Red color)   Actual size of 8.5ct Alexandrite (marquise cut, 20.32×10.16mm, 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 8.5ct Spinel (marquise cut, 20.56×10.28mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
Bluish Green 8.5ct Alexandrite (marquise cut, 20.32×10.16mm) 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
 61% vs 61%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 8.5ct Spinel Marquise (20.56×10.28mm, Red) and 8.5ct Alexandrite Marquise (20.32×10.16mm, 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.


8.5 Ct Spinel (Marquise) 8.5 Ct Alexandrite (Marquise)
20.56×10.28 mm vs 20.32×10.16 mm
150.06 mm²   146.58 mm²
Face-up size outline for 8.5ct Spinel (20.56×10.28mm, marquise cut)
Face-up size outline for 8.5ct Alexandrite (20.32×10.16mm, marquise cut)
8.5ct Spinel Marquise (20.56×10.28mm)
8.5ct Alexandrite Marquise (20.32×10.16mm)
Difference: 2% (3.48 mm²)
8.5ct Spinel (Marquise, 20.56×10.28mm) has approx. 2% more face-up area than 8.5ct Alexandrite (Marquise, 20.32×10.16mm).


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