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4ct Tourmaline (Oval, 13.07×8.71mm, Violet) vs 12ct Topaz (Oval, 18.06×12.04mm, Blue)


Quick summary: When looked from above (face-up position), 12ct Topaz (18.06×12.04mm, oval cut) appears 91% larger than 4ct Tourmaline (13.07×8.71mm, oval cut). See below how they compare side-by-side on a ring and finger.

4ct Tourmaline (oval cut)
vs
 12ct Topaz (oval cut)
violet
 
blue
13.07×8.71 mm 18.06×12.04 mm
actual size
Actual size of 4ct Tourmaline (oval cut, 13.07×8.71mm, Violet color)   Actual size of 12ct Topaz (oval cut, 18.06×12.04mm, Blue color)
 
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Violet 4ct Tourmaline (oval cut, 13.07×8.71mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
Blue 12ct Topaz (oval cut, 18.06×12.04mm) 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
 52% vs 72%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 4ct Tourmaline Oval (13.07×8.71mm, Violet) and 12ct Topaz Oval (18.06×12.04mm, 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, Topaz will face-up smaller than Tourmaline for a given carat weight, because it has higher specific gravity (3.53 vs. 3.06 - this means it's "heavier" compared to Tourmaline 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.


4 Ct Tourmaline (Oval) 12 Ct Topaz (Oval)
13.07×8.71 mm vs 18.06×12.04 mm
93.35 mm²   178.3 mm²
Face-up size outline for 12ct Topaz (18.06×12.04mm, oval cut)
Face-up size outline for 4ct Tourmaline (13.07×8.71mm, oval cut)
4ct Tourmaline Oval (13.07×8.71mm)
12ct Topaz Oval (18.06×12.04mm)
Difference: 91% (84.95 mm²)
12ct Topaz (Oval, 18.06×12.04mm) has approx. 91% more face-up area than 4ct Tourmaline (Oval, 13.07×8.71mm).


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