×
carat vs. color  length*  width*
  ×

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

39ct Ruby (Round, 20.27×20.27mm, Red) vs 1ct Diamond (Round, 6.5×6.5mm, White)


Quick summary: When looked from above (face-up position), 39ct Ruby (20.27×20.27mm, round cut) appears 9.7 times larger than 1ct Diamond (6.5×6.5mm, round cut). See below how they compare side-by-side on a ring and finger.

39ct Ruby (round cut)
vs
 1ct Diamond (round cut)
red
 
white
20.27×20.27 mm 6.5×6.5 mm
actual size
Actual size of 39ct Ruby (round cut, 20.27×20.27mm, Red color)   Actual size of 1ct Diamond (round cut, 6.5×6.5mm, White color)
 
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Red 39ct Ruby (round cut, 20.27×20.27mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
White 1ct Diamond (round cut, 6.5×6.5mm) 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
 120% vs 39%
Saved...
Ring diameter: 16.9 mm
USA UK Asia EU1 EU2
Actual sizes of 39ct Ruby Round (20.27×20.27mm, Red) and 1ct Diamond Round (6.5×6.5mm, 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.


39 Ct Ruby (Round) 1 Ct Diamond (Round)
20.27×20.27 mm vs 6.5×6.5 mm
322.7 mm²   33.18 mm²
Face-up size outline for 39ct Ruby (20.27×20.27mm, round cut)
Face-up size outline for 1ct Diamond (6.5×6.5mm, round cut)
39ct Ruby Round (20.27×20.27mm)
1ct Diamond Round (6.5×6.5mm)
Difference: 873% (289.52 mm²)
39ct Ruby (Round, 20.27×20.27mm) has approx. 873% more face-up area than 1ct Diamond (Round, 6.5×6.5mm). In other words, it's 9.73x larger.


Popular comparisons: