How big is a 3 carat ruby?
By HeyGema™ · Updated
In short
A 3 carat round ruby measures about 8.9 mm across (0.35 inches), 4% narrower than a 3 carat diamond (9.3 mm). An oval of the same weight is 11.1 x 7.6 mm and an emerald cut 9.7 x 6.9 mm.
- 8.9 mmround ruby, across
- 0.35 inthe same in inches
- 0.60 gweight
- 54%of a size 6 finger's width
Carat to mm calculator
About 8.9 x 8.9 mm
An estimate for a well-cut stone. A deep or shallow cut faces up smaller or bigger.
Round
8.9 mm
Oval
11.1 x 7.6 mm
Cushion
7.7 x 7.7 mm
Princess
7.6 x 7.6 mm
Emerald cut
9.7 x 6.9 mm
Asscher
7.6 x 7.6 mm
Radiant
9.0 x 6.9 mm
Pear
11.7 x 7.6 mm
Marquise
14.4 x 7.2 mm
Heart
9.0 x 9.0 mm
Trillion
9.7 x 9.7 mm
Baguette
11.1 x 5.5 mm
= 5 mm in every picture above
3 carat ruby size by shape
Face-up measurements of a well-cut 3 carat ruby. Ruby is denser than diamond (4.00 against 3.52), so it packs more weight into less space and faces up 4% narrower for the same weight.
- Round
- Length x width: 8.9 mm
- In inches: 0.35 in
- Oval
- Length x width: 11.1 x 7.6 mm
- In inches: 0.44 x 0.30 in
- Cushion
- Length x width: 7.7 x 7.7 mm
- In inches: 0.30 x 0.30 in
- Princess
- Length x width: 7.6 x 7.6 mm
- In inches: 0.30 x 0.30 in
- Emerald cut
- Length x width: 9.7 x 6.9 mm
- In inches: 0.38 x 0.27 in
- Asscher
- Length x width: 7.6 x 7.6 mm
- In inches: 0.30 x 0.30 in
- Radiant
- Length x width: 9.0 x 6.9 mm
- In inches: 0.35 x 0.27 in
- Pear
- Length x width: 11.7 x 7.6 mm
- In inches: 0.46 x 0.30 in
- Marquise
- Length x width: 14.4 x 7.2 mm
- In inches: 0.57 x 0.28 in
- Heart
- Length x width: 9.0 x 9.0 mm
- In inches: 0.35 x 0.35 in
- Trillion
- Length x width: 9.7 x 9.7 mm
- In inches: 0.38 x 0.38 in
- Baguette
- Length x width: 11.1 x 5.5 mm
- In inches: 0.44 x 0.22 in
3 carat ruby against other gems
- Diamond
- Round, 3 carat: 9.3 mm
- Moissanite
- Round, 3 carat: 9.6 mm
- Sapphire
- Round, 3 carat: 8.9 mm
- Emerald
- Round, 3 carat: 10.1 mm
- Aquamarine
- Round, 3 carat: 10.2 mm
- Morganite
- Round, 3 carat: 10.0 mm
- Tanzanite
- Round, 3 carat: 9.5 mm
- Topaz
- Round, 3 carat: 9.3 mm
- Ruby (this page)
- Round, 3 carat: 8.9 mm
3 carat ruby on a finger
- 4
- Finger width: 14.9 mm
- Round covers: 60%
- Oval covers: 51%
- 5
- Finger width: 15.7 mm
- Round covers: 57%
- Oval covers: 48%
- 6
- Finger width: 16.5 mm
- Round covers: 54%
- Oval covers: 46%
- 7
- Finger width: 17.3 mm
- Round covers: 51%
- Oval covers: 44%
- 8
- Finger width: 18.1 mm
- Round covers: 49%
- Oval covers: 42%
- 9
- Finger width: 18.9 mm
- Round covers: 47%
- Oval covers: 40%
Ruby at nearby weights
- 2 carat ruby
- Round diameter: 7.8 mm
- 3 ct (this page)
- Round diameter: 8.9 mm
- 4 carat ruby
- Round diameter: 9.8 mm
Questions
A round 3 carat ruby is about 8.9 mm across. Other shapes are longer than they are wide: an oval is 11.1 x 7.6 mm.
No. A round 3 carat ruby is 4% narrower than a 3 carat diamond (9.3 mm).
0.60 grams. A carat is 200 milligrams for every gem.
A round 3 carat ruby covers 54% of the width of a size 6 finger. Compare it with a ring you have tried on in the finger chart above.