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2.5ct Amethyst (Cabochon, 10.65×7.1mm, Violet) vs 2.5ct Tanzanite (Cabochon, 9.86×6.57mm, Blue)


Quick summary: When looked from above (face-up position), 2.5ct Amethyst (10.65×7.1mm, cabochon cut) appears 17% larger than 2.5ct Tanzanite (9.86×6.57mm, cabochon cut). See below how they compare side-by-side on a ring and finger.

2.5ct Amethyst (cabochon cut)
vs
 2.5ct Tanzanite (cabochon cut)
violet
 
blue
10.65×7.1 mm 9.86×6.57 mm
actual size
Actual size of 2.5ct Amethyst (cabochon cut, 10.65×7.1mm, Violet color)   Actual size of 2.5ct Tanzanite (cabochon cut, 9.86×6.57mm, 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 (cabochon cut, 10.65×7.1mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
Blue 2.5ct Tanzanite (cabochon cut, 9.86×6.57mm) 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
 43% vs 39%
Saved...
Ring diameter: 16.9 mm
USA UK Asia EU1 EU2
Actual sizes of 2.5ct Amethyst Cabochon (10.65×7.1mm, Violet) and 2.5ct Tanzanite Cabochon (9.86×6.57mm, 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 (Cabochon) 2.5 Ct Tanzanite (Cabochon)
10.65×7.1 mm vs 9.86×6.57 mm
62 mm²   53.12 mm²
Face-up size outline for 2.5ct Amethyst (10.65×7.1mm, cabochon cut)
Face-up size outline for 2.5ct Tanzanite (9.86×6.57mm, cabochon cut)
2.5ct Amethyst Cabochon (10.65×7.1mm)
2.5ct Tanzanite Cabochon (9.86×6.57mm)
Difference: 17% (8.88 mm²)
2.5ct Amethyst (Cabochon, 10.65×7.1mm) has approx. 17% more face-up area than 2.5ct Tanzanite (Cabochon, 9.86×6.57mm).


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