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18ct Benitoite (Trillion, 19.75×19.75mm, Blue) vs 18ct Alexandrite (Trillion, 19.61×19.61mm, Bluish Green)


Quick summary: When looked from above (face-up position), 18ct Benitoite (19.75×19.75mm, trillion cut) appears 1% larger than 18ct Alexandrite (19.61×19.61mm, trillion cut). See below how they compare side-by-side on a ring and finger.

18ct Benitoite (trillion cut)
vs
 18ct Alexandrite (trillion cut)
blue
 
bluish green
19.75×19.75 mm 19.61×19.61 mm
actual size
Actual size of 18ct Benitoite (trillion cut, 19.75×19.75mm, Blue color)   Actual size of 18ct Alexandrite (trillion cut, 19.61×19.61mm, 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 (trillion cut, 19.75×19.75mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
Bluish Green 18ct Alexandrite (trillion cut, 19.61×19.61mm) 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
 117% vs 117%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 18ct Benitoite Trillion (19.75×19.75mm, Blue) and 18ct Alexandrite Trillion (19.61×19.61mm, 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 (Trillion) 18 Ct Alexandrite (Trillion)
19.75×19.75 mm vs 19.61×19.61 mm
241.84 mm²   238.42 mm²
Face-up size outline for 18ct Benitoite (19.75×19.75mm, trillion cut)
Face-up size outline for 18ct Alexandrite (19.61×19.61mm, trillion cut)
18ct Benitoite Trillion (19.75×19.75mm)
18ct Alexandrite Trillion (19.61×19.61mm)
Difference: 1% (3.42 mm²)
18ct Benitoite (Trillion, 19.75×19.75mm) has approx. 1% more face-up area than 18ct Alexandrite (Trillion, 19.61×19.61mm).


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