How big is a 0.5 carat opal?
By HeyGema™ · Updated
In short
A 0.5 carat round opal measures about 6.1 mm across (0.24 inches), 19% wider than a 0.5 carat diamond (5.1 mm). An oval of the same weight is 7.5 x 5.2 mm and an emerald cut 6.6 x 4.7 mm.
- 6.1 mmround opal, across
- 0.24 inthe same in inches
- 0.10 gweight
- 37%of a size 6 finger's width
Carat to mm calculator
About 6.1 x 6.1 mm
An estimate for a well-cut stone. A deep or shallow cut faces up smaller or bigger.
Round
6.1 mm
Oval
7.5 x 5.2 mm
Cushion
5.3 x 5.3 mm
Princess
5.2 x 5.2 mm
Emerald cut
6.6 x 4.7 mm
Asscher
5.2 x 5.2 mm
Radiant
6.1 x 4.7 mm
Pear
8.0 x 5.2 mm
Marquise
9.8 x 4.9 mm
Heart
6.1 x 6.1 mm
Trillion
6.6 x 6.6 mm
Baguette
7.5 x 3.8 mm
= 2 mm in every picture above
0.5 carat opal size by shape
Face-up measurements of a well-cut 0.5 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: 6.1 mm
- In inches: 0.24 in
- Oval
- Length x width: 7.5 x 5.2 mm
- In inches: 0.30 x 0.20 in
- Cushion
- Length x width: 5.3 x 5.3 mm
- In inches: 0.21 x 0.21 in
- Princess
- Length x width: 5.2 x 5.2 mm
- In inches: 0.20 x 0.20 in
- Emerald cut
- Length x width: 6.6 x 4.7 mm
- In inches: 0.26 x 0.19 in
- Asscher
- Length x width: 5.2 x 5.2 mm
- In inches: 0.20 x 0.20 in
- Radiant
- Length x width: 6.1 x 4.7 mm
- In inches: 0.24 x 0.19 in
- Pear
- Length x width: 8.0 x 5.2 mm
- In inches: 0.32 x 0.20 in
- Marquise
- Length x width: 9.8 x 4.9 mm
- In inches: 0.39 x 0.19 in
- Heart
- Length x width: 6.1 x 6.1 mm
- In inches: 0.24 x 0.24 in
- Trillion
- Length x width: 6.6 x 6.6 mm
- In inches: 0.26 x 0.26 in
- Baguette
- Length x width: 7.5 x 3.8 mm
- In inches: 0.30 x 0.15 in
0.5 carat opal against other gems
- Diamond
- Round, 0.5 carat: 5.1 mm
- Moissanite
- Round, 0.5 carat: 5.3 mm
- Sapphire
- Round, 0.5 carat: 4.9 mm
- Ruby
- Round, 0.5 carat: 4.9 mm
- Emerald
- Round, 0.5 carat: 5.6 mm
- Aquamarine
- Round, 0.5 carat: 5.6 mm
- Morganite
- Round, 0.5 carat: 5.5 mm
- Tanzanite
- Round, 0.5 carat: 5.2 mm
- Opal (this page)
- Round, 0.5 carat: 6.1 mm
0.5 carat opal on a finger
- 4
- Finger width: 14.9 mm
- Round covers: 41%
- Oval covers: 35%
- 5
- Finger width: 15.7 mm
- Round covers: 39%
- Oval covers: 33%
- 6
- Finger width: 16.5 mm
- Round covers: 37%
- Oval covers: 31%
- 7
- Finger width: 17.3 mm
- Round covers: 35%
- Oval covers: 30%
- 8
- Finger width: 18.1 mm
- Round covers: 34%
- Oval covers: 29%
- 9
- Finger width: 18.9 mm
- Round covers: 32%
- Oval covers: 27%
Opal at nearby weights
- 0.5 ct (this page)
- Round diameter: 6.1 mm
- 1 carat opal
- Round diameter: 7.7 mm
Questions
A round 0.5 carat opal is about 6.1 mm across. Other shapes are longer than they are wide: an oval is 7.5 x 5.2 mm.
Yes. A round 0.5 carat opal is 19% wider than a 0.5 carat diamond (5.1 mm).
0.10 grams. A carat is 200 milligrams for every gem.
A round 0.5 carat opal covers 37% of the width of a size 6 finger. Compare it with a ring you have tried on in the finger chart above.