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20ct Spinel (Emerald, 17.96×13.3mm, Red) vs 8ct Diamond (Emerald, 13.37×9.9mm, White)


Quick summary: When looked from above (face-up position), 20ct Spinel (17.96×13.3mm, emerald cut) appears 80% larger than 8ct Diamond (13.37×9.9mm, emerald cut). See below how they compare side-by-side on a ring and finger.

20ct Spinel (emerald cut)
vs
 8ct Diamond (emerald cut)
red
 
white
17.96×13.3 mm 13.37×9.9 mm
actual size
Actual size of 20ct Spinel (emerald cut, 17.96×13.3mm, Red color)   Actual size of 8ct Diamond (emerald cut, 13.37×9.9mm, 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 (emerald cut, 17.96×13.3mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
White 8ct Diamond (emerald cut, 13.37×9.9mm) 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 59%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 20ct Spinel Emerald (17.96×13.3mm, Red) and 8ct Diamond Emerald (13.37×9.9mm, 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 (Emerald) 8 Ct Diamond (Emerald)
17.96×13.3 mm vs 13.37×9.9 mm
222.15 mm²   123.1 mm²
Face-up size outline for 20ct Spinel (17.96×13.3mm, emerald cut)
Face-up size outline for 8ct Diamond (13.37×9.9mm, emerald cut)
20ct Spinel Emerald (17.96×13.3mm)
8ct Diamond Emerald (13.37×9.9mm)
Difference: 80% (99.05 mm²)
20ct Spinel (Emerald, 17.96×13.3mm) has approx. 80% more face-up area than 8ct Diamond (Emerald, 13.37×9.9mm).


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