×
carat vs. color  length*  width*
  ×

(or examine a )
* size in mm (optional)

3ct Ruby (Round, 8.62×8.62mm, Red) vs 3ct Diamond (Round, 9.37×9.37mm, White)


Quick summary: When looked from above (face-up position), 3ct Diamond (9.37×9.37mm, round cut) appears 18% larger than 3ct Ruby (8.62×8.62mm, round cut). See below how they compare side-by-side on a ring and finger.

3ct Ruby (round cut)
vs
 3ct Diamond (round cut)
red
 
white
8.62×8.62 mm 9.37×9.37 mm
actual size
Actual size of 3ct Ruby (round cut, 8.62×8.62mm, Red color)   Actual size of 3ct Diamond (round cut, 9.37×9.37mm, White color)
 
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Red 3ct Ruby (round cut, 8.62×8.62mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
White 3ct Diamond (round cut, 9.37×9.37mm) 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 56%
Saved...
Ring diameter: 16.9 mm
USA UK Asia EU1 EU2
Actual sizes of 3ct Ruby Round (8.62×8.62mm, Red) and 3ct Diamond Round (9.37×9.37mm, 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.


3 Ct Ruby (Round) 3 Ct Diamond (Round)
8.62×8.62 mm vs 9.37×9.37 mm
58.36 mm²   68.96 mm²
Face-up size outline for 3ct Diamond (9.37×9.37mm, round cut)
Face-up size outline for 3ct Ruby (8.62×8.62mm, round cut)
3ct Ruby Round (8.62×8.62mm)
3ct Diamond Round (9.37×9.37mm)
Difference: 18% (10.6 mm²)
3ct Diamond (Round, 9.37×9.37mm) has approx. 18% more face-up area than 3ct Ruby (Round, 8.62×8.62mm).


Popular comparisons: