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30ct Amethyst (Round, 21.31×21.31mm, Violet) vs 30ct Alexandrite (Round, 19.01×19.01mm, Bluish Green)


Quick summary: When looked from above (face-up position), 30ct Amethyst (21.31×21.31mm, round cut) appears 26% larger than 30ct Alexandrite (19.01×19.01mm, round cut). See below how they compare side-by-side on a ring and finger.

30ct Amethyst (round cut)
vs
 30ct Alexandrite (round cut)
violet
 
bluish green
21.31×21.31 mm 19.01×19.01 mm
actual size
Actual size of 30ct Amethyst (round cut, 21.31×21.31mm, Violet color)   Actual size of 30ct Alexandrite (round cut, 19.01×19.01mm, 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 30ct Amethyst (round cut, 21.31×21.31mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
Bluish Green 30ct Alexandrite (round cut, 19.01×19.01mm) 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
 127% vs 113%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 30ct Amethyst Round (21.31×21.31mm, Violet) and 30ct Alexandrite Round (19.01×19.01mm, 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.


30 Ct Amethyst (Round) 30 Ct Alexandrite (Round)
21.31×21.31 mm vs 19.01×19.01 mm
356.66 mm²   283.83 mm²
Face-up size outline for 30ct Amethyst (21.31×21.31mm, round cut)
Face-up size outline for 30ct Alexandrite (19.01×19.01mm, round cut)
30ct Amethyst Round (21.31×21.31mm)
30ct Alexandrite Round (19.01×19.01mm)
Difference: 26% (72.83 mm²)
30ct Amethyst (Round, 21.31×21.31mm) has approx. 26% more face-up area than 30ct Alexandrite (Round, 19.01×19.01mm).


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