How big is a 3 carat opal?
By HeyGema™ · Updated
In short
A 3 carat round opal measures about 11.1 mm across (0.44 inches), 19% wider than a 3 carat diamond (9.3 mm). An oval of the same weight is 13.7 x 9.4 mm and an emerald cut 12.0 x 8.6 mm.
- 11.1 mmround opal, across
- 0.44 inthe same in inches
- 0.60 gweight
- 67%of a size 6 finger's width
Carat to mm calculator
About 11.1 x 11.1 mm
An estimate for a well-cut stone. A deep or shallow cut faces up smaller or bigger.
Round
11.1 mm
Oval
13.7 x 9.4 mm
Cushion
9.6 x 9.6 mm
Princess
9.4 x 9.4 mm
Emerald cut
12.0 x 8.6 mm
Asscher
9.4 x 9.4 mm
Radiant
11.1 x 8.6 mm
Pear
14.6 x 9.4 mm
Marquise
17.8 x 8.9 mm
Heart
11.1 x 11.1 mm
Trillion
12.0 x 12.0 mm
Baguette
13.7 x 6.9 mm
= 5 mm in every picture above
3 carat opal size by shape
Face-up measurements of a well-cut 3 carat opal. Opal is lighter than diamond (2.10 against 3.52), so the same weight gives a bigger stone, 19% wider across.
- Round
- Length x width: 11.1 mm
- In inches: 0.44 in
- Oval
- Length x width: 13.7 x 9.4 mm
- In inches: 0.54 x 0.37 in
- Cushion
- Length x width: 9.6 x 9.6 mm
- In inches: 0.38 x 0.38 in
- Princess
- Length x width: 9.4 x 9.4 mm
- In inches: 0.37 x 0.37 in
- Emerald cut
- Length x width: 12.0 x 8.6 mm
- In inches: 0.47 x 0.34 in
- Asscher
- Length x width: 9.4 x 9.4 mm
- In inches: 0.37 x 0.37 in
- Radiant
- Length x width: 11.1 x 8.6 mm
- In inches: 0.44 x 0.34 in
- Pear
- Length x width: 14.6 x 9.4 mm
- In inches: 0.57 x 0.37 in
- Marquise
- Length x width: 17.8 x 8.9 mm
- In inches: 0.70 x 0.35 in
- Heart
- Length x width: 11.1 x 11.1 mm
- In inches: 0.44 x 0.44 in
- Trillion
- Length x width: 12.0 x 12.0 mm
- In inches: 0.47 x 0.47 in
- Baguette
- Length x width: 13.7 x 6.9 mm
- In inches: 0.54 x 0.27 in
3 carat opal against other gems
- Diamond
- Round, 3 carat: 9.3 mm
- Moissanite
- Round, 3 carat: 9.6 mm
- Sapphire
- Round, 3 carat: 8.9 mm
- Ruby
- 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
- Opal (this page)
- Round, 3 carat: 11.1 mm
3 carat opal on a finger
- 4
- Finger width: 14.9 mm
- Round covers: 74%
- Oval covers: 63%
- 5
- Finger width: 15.7 mm
- Round covers: 70%
- Oval covers: 60%
- 6
- Finger width: 16.5 mm
- Round covers: 67%
- Oval covers: 57%
- 7
- Finger width: 17.3 mm
- Round covers: 64%
- Oval covers: 54%
- 8
- Finger width: 18.1 mm
- Round covers: 61%
- Oval covers: 52%
- 9
- Finger width: 18.9 mm
- Round covers: 58%
- Oval covers: 50%
Opal at nearby weights
- 2 carat opal
- Round diameter: 9.7 mm
- 3 ct (this page)
- Round diameter: 11.1 mm
- 4 carat opal
- Round diameter: 12.2 mm
Questions
A round 3 carat opal is about 11.1 mm across. Other shapes are longer than they are wide: an oval is 13.7 x 9.4 mm.
Yes. A round 3 carat opal is 19% wider than a 3 carat diamond (9.3 mm).
0.60 grams. A carat is 200 milligrams for every gem.
A round 3 carat opal covers 67% of the width of a size 6 finger. Compare it with a ring you have tried on in the finger chart above.