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20ct Benitoite (Radiant, 15.42×15.42mm, Blue) vs 20ct Alexandrite (Radiant, 15.31×15.31mm, Bluish Green)


Quick summary: When looked from above (face-up position), 20ct Benitoite (15.42×15.42mm, radiant cut) appears 1% larger than 20ct Alexandrite (15.31×15.31mm, radiant cut). See below how they compare side-by-side on a ring and finger.

20ct Benitoite (radiant cut)
vs
 20ct Alexandrite (radiant cut)
blue
 
bluish green
15.42×15.42 mm 15.31×15.31 mm
actual size
Actual size of 20ct Benitoite (radiant cut, 15.42×15.42mm, Blue color)   Actual size of 20ct Alexandrite (radiant cut, 15.31×15.31mm, 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 20ct Benitoite (radiant cut, 15.42×15.42mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
Bluish Green 20ct Alexandrite (radiant cut, 15.31×15.31mm) 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
 92% vs 91%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 20ct Benitoite Radiant (15.42×15.42mm, Blue) and 20ct Alexandrite Radiant (15.31×15.31mm, 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.


20 Ct Benitoite (Radiant) 20 Ct Alexandrite (Radiant)
15.42×15.42 mm vs 15.31×15.31 mm
225.89 mm²   222.68 mm²
Face-up size outline for 20ct Benitoite (15.42×15.42mm, radiant cut)
Face-up size outline for 20ct Alexandrite (15.31×15.31mm, radiant cut)
20ct Benitoite Radiant (15.42×15.42mm)
20ct Alexandrite Radiant (15.31×15.31mm)
Difference: 1% (3.21 mm²)
20ct Benitoite (Radiant, 15.42×15.42mm) has approx. 1% more face-up area than 20ct Alexandrite (Radiant, 15.31×15.31mm).


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