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13ct Amethyst (Trillion, 19.72×19.72mm, Violet) vs 13ct Alexandrite (Trillion, 17.59×17.59mm, Bluish Green)


Quick summary: When looked from above (face-up position), 13ct Amethyst (19.72×19.72mm, trillion cut) appears 26% larger than 13ct Alexandrite (17.59×17.59mm, trillion cut). See below how they compare side-by-side on a ring and finger.

13ct Amethyst (trillion cut)
vs
 13ct Alexandrite (trillion cut)
violet
 
bluish green
19.72×19.72 mm 17.59×17.59 mm
actual size
Actual size of 13ct Amethyst (trillion cut, 19.72×19.72mm, Violet color)   Actual size of 13ct Alexandrite (trillion cut, 17.59×17.59mm, Bluish Green color)
 
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Violet 13ct Amethyst (trillion cut, 19.72×19.72mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
Bluish Green 13ct Alexandrite (trillion cut, 17.59×17.59mm) 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 105%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 13ct Amethyst Trillion (19.72×19.72mm, Violet) and 13ct Alexandrite Trillion (17.59×17.59mm, 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 Amethyst for a given carat weight, because it has higher specific gravity (3.73 vs. 2.65 - this means it's "heavier" compared to Amethyst 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.


13 Ct Amethyst (Trillion) 13 Ct Alexandrite (Trillion)
19.72×19.72 mm vs 17.59×17.59 mm
241.1 mm²   191.83 mm²
Face-up size outline for 13ct Amethyst (19.72×19.72mm, trillion cut)
Face-up size outline for 13ct Alexandrite (17.59×17.59mm, trillion cut)
13ct Amethyst Trillion (19.72×19.72mm)
13ct Alexandrite Trillion (17.59×17.59mm)
Difference: 26% (49.27 mm²)
13ct Amethyst (Trillion, 19.72×19.72mm) has approx. 26% more face-up area than 13ct Alexandrite (Trillion, 17.59×17.59mm).


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