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18ct Ruby (Cushion, 14.51×14.51mm, Red) vs 40ct Spinel (Cushion, 19.61×19.61mm, Blue)


Quick summary: When looked from above (face-up position), 40ct Spinel (19.61×19.61mm, cushion cut) appears 83% larger than 18ct Ruby (14.51×14.51mm, cushion cut). See below how they compare side-by-side on a ring and finger.

18ct Ruby (cushion cut)
vs
40ct Spinel (cushion cut)
red
 
blue
14.51×14.51 mm 19.61×19.61 mm
actual size
Actual size of 18ct Ruby (cushion cut, 14.51×14.51mm, Red color)   Actual size of 40ct Spinel (cushion cut, 19.61×19.61mm, Blue color)
 
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Red 18ct Ruby (cushion cut, 14.51×14.51mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
Blue 40ct Spinel (cushion cut, 19.61×19.61mm) 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
86% vs 117%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 18ct Ruby Cushion (14.51×14.51mm, Red) and 40ct Spinel Cushion (19.61×19.61mm, 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, Ruby will face-up smaller than Spinel for a given carat weight, because it has higher specific gravity (4 vs. 3.6 - this means it's "heavier" compared to Spinel 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.


18 Ct Ruby (Cushion) 40 Ct Spinel (Cushion)
14.51×14.51 mm vs 19.61×19.61 mm
189.49 mm²   346.1 mm²
Face-up size outline for 40ct Spinel (19.61×19.61mm, cushion cut)
Face-up size outline for 18ct Ruby (14.51×14.51mm, cushion cut)
18ct Ruby Cushion (14.51×14.51mm)
40ct Spinel Cushion (19.61×19.61mm)
Difference: 83% (156.61 mm²)
40ct Spinel (Cushion, 19.61×19.61mm) has approx. 83% more face-up area than 18ct Ruby (Cushion, 14.51×14.51mm).


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