How big is a 10 carat opal?
By HeyGema™ · Updated
In short
A 10 carat round opal measures about 16.5 mm across (0.65 inches), 19% wider than a 10 carat diamond (13.9 mm). An oval of the same weight is 20.5 x 14.1 mm and an emerald cut 17.9 x 12.8 mm.
- 16.5 mmround opal, across
- 0.65 inthe same in inches
- 2.00 gweight
- 100%of a size 6 finger's width
Carat to mm calculator
About 16.5 x 16.5 mm
An estimate for a well-cut stone. A deep or shallow cut faces up smaller or bigger.
Round
16.5 mm
Oval
20.5 x 14.1 mm
Cushion
14.3 x 14.3 mm
Princess
14.1 x 14.1 mm
Emerald cut
17.9 x 12.8 mm
Asscher
14.1 x 14.1 mm
Radiant
16.6 x 12.8 mm
Pear
21.8 x 14.1 mm
Marquise
26.6 x 13.3 mm
Heart
16.6 x 16.6 mm
Trillion
17.9 x 17.9 mm
Baguette
20.5 x 10.2 mm
= 5 mm in every picture above
10 carat opal size by shape
Face-up measurements of a well-cut 10 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: 16.5 mm
- In inches: 0.65 in
- Oval
- Length x width: 20.5 x 14.1 mm
- In inches: 0.81 x 0.55 in
- Cushion
- Length x width: 14.3 x 14.3 mm
- In inches: 0.56 x 0.56 in
- Princess
- Length x width: 14.1 x 14.1 mm
- In inches: 0.55 x 0.55 in
- Emerald cut
- Length x width: 17.9 x 12.8 mm
- In inches: 0.71 x 0.50 in
- Asscher
- Length x width: 14.1 x 14.1 mm
- In inches: 0.55 x 0.55 in
- Radiant
- Length x width: 16.6 x 12.8 mm
- In inches: 0.65 x 0.50 in
- Pear
- Length x width: 21.8 x 14.1 mm
- In inches: 0.86 x 0.55 in
- Marquise
- Length x width: 26.6 x 13.3 mm
- In inches: 1.05 x 0.52 in
- Heart
- Length x width: 16.6 x 16.6 mm
- In inches: 0.65 x 0.65 in
- Trillion
- Length x width: 17.9 x 17.9 mm
- In inches: 0.71 x 0.71 in
- Baguette
- Length x width: 20.5 x 10.2 mm
- In inches: 0.81 x 0.40 in
10 carat opal against other gems
- Diamond
- Round, 10 carat: 13.9 mm
- Moissanite
- Round, 10 carat: 14.3 mm
- Sapphire
- Round, 10 carat: 13.3 mm
- Ruby
- Round, 10 carat: 13.3 mm
- Emerald
- Round, 10 carat: 15.1 mm
- Aquamarine
- Round, 10 carat: 15.2 mm
- Morganite
- Round, 10 carat: 15.0 mm
- Tanzanite
- Round, 10 carat: 14.1 mm
- Opal (this page)
- Round, 10 carat: 16.5 mm
10 carat opal on a finger
- 4
- Finger width: 14.9 mm
- Round covers: 111%
- Oval covers: 95%
- 5
- Finger width: 15.7 mm
- Round covers: 105%
- Oval covers: 90%
- 6
- Finger width: 16.5 mm
- Round covers: 100%
- Oval covers: 85%
- 7
- Finger width: 17.3 mm
- Round covers: 95%
- Oval covers: 81%
- 8
- Finger width: 18.1 mm
- Round covers: 91%
- Oval covers: 78%
- 9
- Finger width: 18.9 mm
- Round covers: 87%
- Oval covers: 74%
Opal at nearby weights
- 5 carat opal
- Round diameter: 13.1 mm
- 10 ct (this page)
- Round diameter: 16.5 mm
Questions
A round 10 carat opal is about 16.5 mm across. Other shapes are longer than they are wide: an oval is 20.5 x 14.1 mm.
Yes. A round 10 carat opal is 19% wider than a 10 carat diamond (13.9 mm).
2.00 grams. A carat is 200 milligrams for every gem.
A round 10 carat opal covers 100% of the width of a size 6 finger. Compare it with a ring you have tried on in the finger chart above.