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15ct Alexandrite (Princess, 13.26×13.26mm, Bluish Green) vs 15ct Topaz (Princess, 13.51×13.51mm, Blue)


Quick summary: When looked from above (face-up position), 15ct Topaz (13.51×13.51mm, princess cut) appears 4% larger than 15ct Alexandrite (13.26×13.26mm, princess cut). See below how they compare side-by-side on a ring and finger.

15ct Alexandrite (princess cut)
vs
 15ct Topaz (princess cut)
bluish green
 
blue
13.26×13.26 mm 13.51×13.51 mm
actual size
Actual size of 15ct Alexandrite (princess cut, 13.26×13.26mm, Bluish Green color)   Actual size of 15ct Topaz (princess cut, 13.51×13.51mm, Blue color)
 
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Bluish Green 15ct Alexandrite (princess cut, 13.26×13.26mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
Blue 15ct Topaz (princess cut, 13.51×13.51mm) 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
 79% vs 80%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 15ct Alexandrite Princess (13.26×13.26mm, Bluish Green) and 15ct Topaz Princess (13.51×13.51mm, 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, Alexandrite will face-up smaller than Topaz for a given carat weight, because it has higher specific gravity (3.73 vs. 3.53 - this means it's "heavier" compared to Topaz 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.


15 Ct Alexandrite (Princess) 15 Ct Topaz (Princess)
13.26×13.26 mm vs 13.51×13.51 mm
175.83 mm²   182.52 mm²
Face-up size outline for 15ct Topaz (13.51×13.51mm, princess cut)
Face-up size outline for 15ct Alexandrite (13.26×13.26mm, princess cut)
15ct Alexandrite Princess (13.26×13.26mm)
15ct Topaz Princess (13.51×13.51mm)
Difference: 4% (6.69 mm²)
15ct Topaz (Princess, 13.51×13.51mm) has approx. 4% more face-up area than 15ct Alexandrite (Princess, 13.26×13.26mm).


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