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12ct Sapphire (Oval, 17.31×11.54mm, Blue) vs 12ct Tanzanite (Oval, 18.47×12.31mm, Blue)


Quick summary: When looked from above (face-up position), 12ct Tanzanite (18.47×12.31mm, oval cut) appears 14% larger than 12ct Sapphire (17.31×11.54mm, oval cut). See below how they compare side-by-side on a ring and finger.

12ct Sapphire (oval cut)
vs
 12ct Tanzanite (oval cut)
blue
 
blue
17.31×11.54 mm 18.47×12.31 mm
actual size
Actual size of 12ct Sapphire (oval cut, 17.31×11.54mm, Blue color)   Actual size of 12ct Tanzanite (oval cut, 18.47×12.31mm, Blue color)
 
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Blue 12ct Sapphire (oval cut, 17.31×11.54mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
Blue 12ct Tanzanite (oval cut, 18.47×12.31mm) 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
 69% vs 73%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 12ct Sapphire Oval (17.31×11.54mm, Blue) and 12ct Tanzanite Oval (18.47×12.31mm, 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, Sapphire will face-up smaller than Tanzanite for a given carat weight, because it has higher specific gravity (4 vs. 3.35 - this means it's "heavier" compared to Tanzanite 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 Sapphire (Oval) 12 Ct Tanzanite (Oval)
17.31×11.54 mm vs 18.47×12.31 mm
163.8 mm²   186.44 mm²
Face-up size outline for 12ct Tanzanite (18.47×12.31mm, oval cut)
Face-up size outline for 12ct Sapphire (17.31×11.54mm, oval cut)
12ct Sapphire Oval (17.31×11.54mm)
12ct Tanzanite Oval (18.47×12.31mm)
Difference: 14% (22.64 mm²)
12ct Tanzanite (Oval, 18.47×12.31mm) has approx. 14% more face-up area than 12ct Sapphire (Oval, 17.31×11.54mm).


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