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18ct Benitoite (Oval, 20.72×13.81mm, Blue) vs 18ct Alexandrite (Oval, 20.57×13.71mm, Bluish Green)


Quick summary: When looked from above (face-up position), 18ct Benitoite (20.72×13.81mm, oval cut) appears 1% larger than 18ct Alexandrite (20.57×13.71mm, oval cut). See below how they compare side-by-side on a ring and finger.

18ct Benitoite (oval cut)
vs
 18ct Alexandrite (oval cut)
blue
 
bluish green
20.72×13.81 mm 20.57×13.71 mm
actual size
Actual size of 18ct Benitoite (oval cut, 20.72×13.81mm, Blue color)   Actual size of 18ct Alexandrite (oval cut, 20.57×13.71mm, Bluish Green color)
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Blue 18ct Benitoite (oval cut, 20.72×13.81mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
Bluish Green 18ct Alexandrite (oval cut, 20.57×13.71mm) 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
 82% vs 82%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 18ct Benitoite Oval (20.72×13.81mm, Blue) and 18ct Alexandrite Oval (20.57×13.71mm, 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 slightly smaller than Benitoite for a given carat weight, because it has higher specific gravity (3.73 vs. 3.65 - this means it's "slightly heavier" compared to Benitoite 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.


18 Ct Benitoite (Oval) 18 Ct Alexandrite (Oval)
20.72×13.81 mm vs 20.57×13.71 mm
234.64 mm²   231.25 mm²
Face-up size outline for 18ct Benitoite (20.72×13.81mm, oval cut)
Face-up size outline for 18ct Alexandrite (20.57×13.71mm, oval cut)
18ct Benitoite Oval (20.72×13.81mm)
18ct Alexandrite Oval (20.57×13.71mm)
Difference: 1% (3.39 mm²)
18ct Benitoite (Oval, 20.72×13.81mm) has approx. 1% more face-up area than 18ct Alexandrite (Oval, 20.57×13.71mm).


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