How big is a 4 carat aquamarine?

By HeyGema™ · Updated

In short

A 4 carat round aquamarine measures about 11.2 mm across (0.44 inches), 9% wider than a 4 carat diamond (10.2 mm). An oval of the same weight is 13.9 x 9.5 mm and an emerald cut 12.1 x 8.7 mm.

Carat to mm calculator

About 11.2 x 11.2 mm

An estimate for a well-cut stone. A deep or shallow cut faces up smaller or bigger.

Round
11.2 mm
Oval
13.9 x 9.5 mm
Cushion
9.7 x 9.7 mm
Princess
9.5 x 9.5 mm
Emerald cut
12.1 x 8.7 mm
Asscher
9.5 x 9.5 mm
Radiant
11.3 x 8.7 mm
Pear
14.7 x 9.5 mm
Marquise
18.0 x 9.0 mm
Heart
11.3 x 11.3 mm
Trillion
12.1 x 12.1 mm
Baguette
13.9 x 6.9 mm
= 5 mm in every picture above
A 4 carat aquamarine in 12 shapes, drawn to one scale.

4 carat aquamarine size by shape

Face-up measurements of a well-cut 4 carat aquamarine. Aquamarine is lighter than diamond (2.70 against 3.52), so the same weight gives a bigger stone, 9% wider across.

Round
Length x width: 11.2 mm
In inches: 0.44 in
Oval
Length x width: 13.9 x 9.5 mm
In inches: 0.55 x 0.38 in
Cushion
Length x width: 9.7 x 9.7 mm
In inches: 0.38 x 0.38 in
Princess
Length x width: 9.5 x 9.5 mm
In inches: 0.38 x 0.38 in
Emerald cut
Length x width: 12.1 x 8.7 mm
In inches: 0.48 x 0.34 in
Asscher
Length x width: 9.5 x 9.5 mm
In inches: 0.38 x 0.38 in
Radiant
Length x width: 11.3 x 8.7 mm
In inches: 0.44 x 0.34 in
Pear
Length x width: 14.7 x 9.5 mm
In inches: 0.58 x 0.38 in
Marquise
Length x width: 18.0 x 9.0 mm
In inches: 0.71 x 0.36 in
Heart
Length x width: 11.3 x 11.3 mm
In inches: 0.44 x 0.44 in
Trillion
Length x width: 12.1 x 12.1 mm
In inches: 0.48 x 0.48 in
Baguette
Length x width: 13.9 x 6.9 mm
In inches: 0.55 x 0.27 in

4 carat aquamarine against other gems

Diamond
Round, 4 carat: 10.2 mm
Moissanite
Round, 4 carat: 10.5 mm
Sapphire
Round, 4 carat: 9.8 mm
Ruby
Round, 4 carat: 9.8 mm
Emerald
Round, 4 carat: 11.2 mm
Morganite
Round, 4 carat: 11.1 mm
Tanzanite
Round, 4 carat: 10.4 mm
Topaz
Round, 4 carat: 10.2 mm
Aquamarine (this page)
Round, 4 carat: 11.2 mm

4 carat aquamarine on a finger

11.2 mm
11.2 mm stone on a 16.5 mm finger: it covers 68% of the widthA round 4 carat aquamarine on a size 6 finger.
4
Finger width: 14.9 mm
Round covers: 75%
Oval covers: 64%
5
Finger width: 15.7 mm
Round covers: 71%
Oval covers: 61%
6
Finger width: 16.5 mm
Round covers: 68%
Oval covers: 58%
7
Finger width: 17.3 mm
Round covers: 65%
Oval covers: 55%
8
Finger width: 18.1 mm
Round covers: 62%
Oval covers: 53%
9
Finger width: 18.9 mm
Round covers: 59%
Oval covers: 50%

Aquamarine at nearby weights

3 carat aquamarine
Round diameter: 10.2 mm
4 ct (this page)
Round diameter: 11.2 mm
5 carat aquamarine
Round diameter: 12.0 mm

Questions

A round 4 carat aquamarine is about 11.2 mm across. Other shapes are longer than they are wide: an oval is 13.9 x 9.5 mm.
Yes. A round 4 carat aquamarine is 9% wider than a 4 carat diamond (10.2 mm).
0.80 grams. A carat is 200 milligrams for every gem.
A round 4 carat aquamarine covers 68% of the width of a size 6 finger. Compare it with a ring you have tried on in the finger chart above.

More size charts