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20ct Spinel (Round, 16.81×16.81mm, Red) vs 20ct Diamond (Round, 17.64×17.64mm, White)


Quick summary: When looked from above (face-up position), 20ct Diamond (17.64×17.64mm, round cut) appears 10% larger than 20ct Spinel (16.81×16.81mm, round cut). See below how they compare side-by-side on a ring and finger.

20ct Spinel (round cut)
vs
 20ct Diamond (round cut)
red
 
white
16.81×16.81 mm 17.64×17.64 mm
actual size
Actual size of 20ct Spinel (round cut, 16.81×16.81mm, Red color)   Actual size of 20ct Diamond (round cut, 17.64×17.64mm, White color)
 
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Red 20ct Spinel (round cut, 16.81×16.81mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
White 20ct Diamond (round cut, 17.64×17.64mm) 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
 100% vs 105%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 20ct Spinel Round (16.81×16.81mm, Red) and 20ct Diamond Round (17.64×17.64mm, White) 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, Spinel will face-up slightly smaller than Diamond for a given carat weight, because it has higher specific gravity (3.6 vs. 3.52 - this means it's "slightly heavier" compared to Diamond 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.


20 Ct Spinel (Round) 20 Ct Diamond (Round)
16.81×16.81 mm vs 17.64×17.64 mm
221.93 mm²   244.39 mm²
Face-up size outline for 20ct Diamond (17.64×17.64mm, round cut)
Face-up size outline for 20ct Spinel (16.81×16.81mm, round cut)
20ct Spinel Round (16.81×16.81mm)
20ct Diamond Round (17.64×17.64mm)
Difference: 10% (22.46 mm²)
20ct Diamond (Round, 17.64×17.64mm) has approx. 10% more face-up area than 20ct Spinel (Round, 16.81×16.81mm).


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