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2.5ct Amethyst (Round, 9.31×9.31mm, Violet) vs 2.5ct Tanzanite (Round, 8.61×8.61mm, Blue)


Quick summary: When looked from above (face-up position), 2.5ct Amethyst (9.31×9.31mm, round cut) appears 17% larger than 2.5ct Tanzanite (8.61×8.61mm, round cut). See below how they compare side-by-side on a ring and finger.

2.5ct Amethyst (round cut)
vs
 2.5ct Tanzanite (round cut)
violet
 
blue
9.31×9.31 mm 8.61×8.61 mm
actual size
Actual size of 2.5ct Amethyst (round cut, 9.31×9.31mm, Violet color)   Actual size of 2.5ct Tanzanite (round cut, 8.61×8.61mm, Blue color)
 
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Violet 2.5ct Amethyst (round cut, 9.31×9.31mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
Blue 2.5ct Tanzanite (round cut, 8.61×8.61mm) 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
 56% vs 51%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 2.5ct Amethyst Round (9.31×9.31mm, Violet) and 2.5ct Tanzanite Round (8.61×8.61mm, Blue) 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, Tanzanite will face-up smaller than Amethyst for a given carat weight, because it has higher specific gravity (3.35 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.


2.5 Ct Amethyst (Round) 2.5 Ct Tanzanite (Round)
9.31×9.31 mm vs 8.61×8.61 mm
68.08 mm²   58.22 mm²
Face-up size outline for 2.5ct Amethyst (9.31×9.31mm, round cut)
Face-up size outline for 2.5ct Tanzanite (8.61×8.61mm, round cut)
2.5ct Amethyst Round (9.31×9.31mm)
2.5ct Tanzanite Round (8.61×8.61mm)
Difference: 17% (9.86 mm²)
2.5ct Amethyst (Round, 9.31×9.31mm) has approx. 17% more face-up area than 2.5ct Tanzanite (Round, 8.61×8.61mm).


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