How big is a 4 carat garnet?

By HeyGema™ · Updated

In short

A 4 carat round garnet measures about 9.9 mm across (0.39 inches), 3% narrower than a 4 carat diamond (10.2 mm). An oval of the same weight is 12.3 x 8.4 mm and an emerald cut 10.7 x 7.7 mm.

Carat to mm calculator

About 9.9 x 9.9 mm

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

Round
9.9 mm
Oval
12.3 x 8.4 mm
Cushion
8.6 x 8.6 mm
Princess
8.4 x 8.4 mm
Emerald cut
10.7 x 7.7 mm
Asscher
8.4 x 8.4 mm
Radiant
10.0 x 7.7 mm
Pear
13.0 x 8.4 mm
Marquise
16.0 x 8.0 mm
Heart
10.0 x 10.0 mm
Trillion
10.7 x 10.7 mm
Baguette
12.3 x 6.1 mm
= 5 mm in every picture above
A 4 carat garnet in 12 shapes, drawn to one scale.

4 carat garnet size by shape

Face-up measurements of a well-cut 4 carat garnet. Garnet is denser than diamond (3.90 against 3.52), so it packs more weight into less space and faces up 3% narrower for the same weight.

Round
Length x width: 9.9 mm
In inches: 0.39 in
Oval
Length x width: 12.3 x 8.4 mm
In inches: 0.48 x 0.33 in
Cushion
Length x width: 8.6 x 8.6 mm
In inches: 0.34 x 0.34 in
Princess
Length x width: 8.4 x 8.4 mm
In inches: 0.33 x 0.33 in
Emerald cut
Length x width: 10.7 x 7.7 mm
In inches: 0.42 x 0.30 in
Asscher
Length x width: 8.4 x 8.4 mm
In inches: 0.33 x 0.33 in
Radiant
Length x width: 10.0 x 7.7 mm
In inches: 0.39 x 0.30 in
Pear
Length x width: 13.0 x 8.4 mm
In inches: 0.51 x 0.33 in
Marquise
Length x width: 16.0 x 8.0 mm
In inches: 0.63 x 0.31 in
Heart
Length x width: 10.0 x 10.0 mm
In inches: 0.39 x 0.39 in
Trillion
Length x width: 10.7 x 10.7 mm
In inches: 0.42 x 0.42 in
Baguette
Length x width: 12.3 x 6.1 mm
In inches: 0.48 x 0.24 in

4 carat garnet 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
Aquamarine
Round, 4 carat: 11.2 mm
Morganite
Round, 4 carat: 11.1 mm
Tanzanite
Round, 4 carat: 10.4 mm
Garnet (this page)
Round, 4 carat: 9.9 mm

4 carat garnet on a finger

9.9 mm
9.9 mm stone on a 16.5 mm finger: it covers 60% of the widthA round 4 carat garnet on a size 6 finger.
4
Finger width: 14.9 mm
Round covers: 66%
Oval covers: 57%
5
Finger width: 15.7 mm
Round covers: 63%
Oval covers: 54%
6
Finger width: 16.5 mm
Round covers: 60%
Oval covers: 51%
7
Finger width: 17.3 mm
Round covers: 57%
Oval covers: 49%
8
Finger width: 18.1 mm
Round covers: 55%
Oval covers: 47%
9
Finger width: 18.9 mm
Round covers: 52%
Oval covers: 45%

Garnet at nearby weights

3 carat garnet
Round diameter: 9.0 mm
4 ct (this page)
Round diameter: 9.9 mm
5 carat garnet
Round diameter: 10.7 mm

Questions

A round 4 carat garnet is about 9.9 mm across. Other shapes are longer than they are wide: an oval is 12.3 x 8.4 mm.
No. A round 4 carat garnet is 3% narrower than a 4 carat diamond (10.2 mm).
0.80 grams. A carat is 200 milligrams for every gem.
A round 4 carat garnet covers 60% 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