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12ct Alexandrite (Princess, 12.31×12.31mm, Bluish Green) vs 12ct Topaz (Princess, 12.54×12.54mm, Blue)


Quick summary: When looked from above (face-up position), 12ct Topaz (12.54×12.54mm, princess cut) appears 4% larger than 12ct Alexandrite (12.31×12.31mm, princess cut). See below how they compare side-by-side on a ring and finger.

12ct Alexandrite (princess cut)
vs
 12ct Topaz (princess cut)
bluish green
 
blue
12.31×12.31 mm 12.54×12.54 mm
actual size
Actual size of 12ct Alexandrite (princess cut, 12.31×12.31mm, Bluish Green color)   Actual size of 12ct Topaz (princess cut, 12.54×12.54mm, 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 12ct Alexandrite (princess cut, 12.31×12.31mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
Blue 12ct Topaz (princess cut, 12.54×12.54mm) 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
 73% vs 75%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 12ct Alexandrite Princess (12.31×12.31mm, Bluish Green) and 12ct Topaz Princess (12.54×12.54mm, 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.


12 Ct Alexandrite (Princess) 12 Ct Topaz (Princess)
12.31×12.31 mm vs 12.54×12.54 mm
151.54 mm²   157.25 mm²
Face-up size outline for 12ct Topaz (12.54×12.54mm, princess cut)
Face-up size outline for 12ct Alexandrite (12.31×12.31mm, princess cut)
12ct Alexandrite Princess (12.31×12.31mm)
12ct Topaz Princess (12.54×12.54mm)
Difference: 4% (5.71 mm²)
12ct Topaz (Princess, 12.54×12.54mm) has approx. 4% more face-up area than 12ct Alexandrite (Princess, 12.31×12.31mm).


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