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8.5ct Amethyst (Cabochon, 16.02×10.68mm, Violet) vs 8.5ct Tanzanite (Cabochon, 14.82×9.88mm, Blue)


Quick summary: When looked from above (face-up position), 8.5ct Amethyst (16.02×10.68mm, cabochon cut) appears 17% larger than 8.5ct Tanzanite (14.82×9.88mm, cabochon cut). See below how they compare side-by-side on a ring and finger.

8.5ct Amethyst (cabochon cut)
vs
8.5ct Tanzanite (cabochon cut)
violet
 
blue
16.02×10.68 mm 14.82×9.88 mm
actual size
Actual size of 8.5ct Amethyst (cabochon cut, 16.02×10.68mm, Violet color)   Actual size of 8.5ct Tanzanite (cabochon cut, 14.82×9.88mm, Blue color)
 
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Violet 8.5ct Amethyst (cabochon cut, 16.02×10.68mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
Blue 8.5ct Tanzanite (cabochon cut, 14.82×9.88mm) 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
64% vs 59%
Saved...
Ring diameter: 16.9 mm
USA UK Asia EU1 EU2
Actual sizes of 8.5ct Amethyst Cabochon (16.02×10.68mm, Violet) and 8.5ct Tanzanite Cabochon (14.82×9.88mm, 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.


8.5 Ct Amethyst (Cabochon) 8.5 Ct Tanzanite (Cabochon)
16.02×10.68 mm vs 14.82×9.88 mm
140.3 mm²   120.07 mm²
Face-up size outline for 8.5ct Amethyst (16.02×10.68mm, cabochon cut)
Face-up size outline for 8.5ct Tanzanite (14.82×9.88mm, cabochon cut)
8.5ct Amethyst Cabochon (16.02×10.68mm)
8.5ct Tanzanite Cabochon (14.82×9.88mm)
Difference: 17% (20.23 mm²)
8.5ct Amethyst (Cabochon, 16.02×10.68mm) has approx. 17% more face-up area than 8.5ct Tanzanite (Cabochon, 14.82×9.88mm).


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