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15ct Amethyst (Round, 16.91×16.91mm, Violet) vs 15ct Alexandrite (Round, 15.09×15.09mm, Bluish Green)


Quick summary: When looked from above (face-up position), 15ct Amethyst (16.91×16.91mm, round cut) appears 26% larger than 15ct Alexandrite (15.09×15.09mm, round cut). See below how they compare side-by-side on a ring and finger.

15ct Amethyst (round cut)
vs
 15ct Alexandrite (round cut)
violet
 
bluish green
16.91×16.91 mm 15.09×15.09 mm
actual size
Actual size of 15ct Amethyst (round cut, 16.91×16.91mm, Violet color)   Actual size of 15ct Alexandrite (round cut, 15.09×15.09mm, 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 15ct Amethyst (round cut, 16.91×16.91mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
Bluish Green 15ct Alexandrite (round cut, 15.09×15.09mm) 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
 101% vs 90%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 15ct Amethyst Round (16.91×16.91mm, Violet) and 15ct Alexandrite Round (15.09×15.09mm, 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.


15 Ct Amethyst (Round) 15 Ct Alexandrite (Round)
16.91×16.91 mm vs 15.09×15.09 mm
224.58 mm²   178.84 mm²
Face-up size outline for 15ct Amethyst (16.91×16.91mm, round cut)
Face-up size outline for 15ct Alexandrite (15.09×15.09mm, round cut)
15ct Amethyst Round (16.91×16.91mm)
15ct Alexandrite Round (15.09×15.09mm)
Difference: 26% (45.74 mm²)
15ct Amethyst (Round, 16.91×16.91mm) has approx. 26% more face-up area than 15ct Alexandrite (Round, 15.09×15.09mm).


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