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18ct Amethyst (Cushion, 16.64×16.64mm, Violet) vs 18ct Alexandrite (Cushion, 14.85×14.85mm, Bluish Green)


Quick summary: When looked from above (face-up position), 18ct Amethyst (16.64×16.64mm, cushion cut) appears 26% larger than 18ct Alexandrite (14.85×14.85mm, cushion cut). See below how they compare side-by-side on a ring and finger.

18ct Amethyst (cushion cut)
vs
 18ct Alexandrite (cushion cut)
violet
 
bluish green
16.64×16.64 mm 14.85×14.85 mm
actual size
Actual size of 18ct Amethyst (cushion cut, 16.64×16.64mm, Violet color)   Actual size of 18ct Alexandrite (cushion cut, 14.85×14.85mm, 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 18ct Amethyst (cushion cut, 16.64×16.64mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
Bluish Green 18ct Alexandrite (cushion cut, 14.85×14.85mm) 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
 99% vs 88%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 18ct Amethyst Cushion (16.64×16.64mm, Violet) and 18ct Alexandrite Cushion (14.85×14.85mm, 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.


18 Ct Amethyst (Cushion) 18 Ct Alexandrite (Cushion)
16.64×16.64 mm vs 14.85×14.85 mm
249.2 mm²   198.47 mm²
Face-up size outline for 18ct Amethyst (16.64×16.64mm, cushion cut)
Face-up size outline for 18ct Alexandrite (14.85×14.85mm, cushion cut)
18ct Amethyst Cushion (16.64×16.64mm)
18ct Alexandrite Cushion (14.85×14.85mm)
Difference: 26% (50.73 mm²)
18ct Amethyst (Cushion, 16.64×16.64mm) has approx. 26% more face-up area than 18ct Alexandrite (Cushion, 14.85×14.85mm).


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