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0.45ct Ruby (Cabochon, 5.25×3.5mm, Red) vs 1.21ct Diamond (Round, 6.93×6.93mm, White)


Quick summary: When looked from above (face-up position), 1.21ct Diamond (6.93×6.93mm, round cut) appears 2.5 times larger than 0.45ct Ruby (5.25×3.5mm, cabochon cut). See below how they compare side-by-side on a ring and finger.

0.45ct Ruby (cabochon cut)
vs
 1.21ct Diamond (round cut)
red
 
white
5.25×3.5 mm 6.93×6.93 mm
actual size
Actual size of 0.45ct Ruby (cabochon cut, 5.25×3.5mm, Red color)   Actual size of 1.21ct Diamond (round cut, 6.93×6.93mm, White color)
 
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Red 0.45ct Ruby (cabochon cut, 5.25×3.5mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
White 1.21ct Diamond (round cut, 6.93×6.93mm) 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
 21% vs 42%
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Ring diameter: 16.9 mm
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Actual sizes of 0.45ct Ruby Cabochon (5.25×3.5mm, Red) and 1.21ct Diamond Round (6.93×6.93mm, 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, Ruby will face-up smaller than Diamond for a given carat weight, because it has higher specific gravity (4 vs. 3.52 - this means it's "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.


0.45 Ct Ruby (Cabochon) 1.21 Ct Diamond (Round)
5.25×3.5 mm vs 6.93×6.93 mm
15.07 mm²   37.72 mm²
Face-up size outline for 1.21ct Diamond (6.93×6.93mm, round cut)
Face-up size outline for 0.45ct Ruby (5.25×3.5mm, cabochon cut)
0.45ct Ruby Cabochon (5.25×3.5mm)
1.21ct Diamond Round (6.93×6.93mm)
Difference: 150% (22.65 mm²)
1.21ct Diamond (Round, 6.93×6.93mm) has approx. 150% more face-up area than 0.45ct Ruby (Cabochon, 5.25×3.5mm). In other words, it's 2.5x larger.


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