How big is a 3 carat garnet?

By HeyGema™ · Updated

In short

A 3 carat round garnet measures about 9.0 mm across (0.35 inches), 3% narrower than a 3 carat diamond (9.3 mm). An oval of the same weight is 11.2 x 7.7 mm and an emerald cut 9.8 x 7.0 mm.

Carat to mm calculator

About 9.0 x 9.0 mm

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

Round
9.0 mm
Oval
11.2 x 7.7 mm
Cushion
7.8 x 7.8 mm
Princess
7.7 x 7.7 mm
Emerald cut
9.8 x 7.0 mm
Asscher
7.7 x 7.7 mm
Radiant
9.1 x 7.0 mm
Pear
11.8 x 7.7 mm
Marquise
14.5 x 7.2 mm
Heart
9.1 x 9.1 mm
Trillion
9.8 x 9.8 mm
Baguette
11.2 x 5.6 mm
= 5 mm in every picture above
A 3 carat garnet in 12 shapes, drawn to one scale.

3 carat garnet size by shape

Face-up measurements of a well-cut 3 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: 9.0 mm
In inches: 0.35 in
Oval
Length x width: 11.2 x 7.7 mm
In inches: 0.44 x 0.30 in
Cushion
Length x width: 7.8 x 7.8 mm
In inches: 0.31 x 0.31 in
Princess
Length x width: 7.7 x 7.7 mm
In inches: 0.30 x 0.30 in
Emerald cut
Length x width: 9.8 x 7.0 mm
In inches: 0.38 x 0.27 in
Asscher
Length x width: 7.7 x 7.7 mm
In inches: 0.30 x 0.30 in
Radiant
Length x width: 9.1 x 7.0 mm
In inches: 0.36 x 0.27 in
Pear
Length x width: 11.8 x 7.7 mm
In inches: 0.47 x 0.30 in
Marquise
Length x width: 14.5 x 7.2 mm
In inches: 0.57 x 0.29 in
Heart
Length x width: 9.1 x 9.1 mm
In inches: 0.36 x 0.36 in
Trillion
Length x width: 9.8 x 9.8 mm
In inches: 0.38 x 0.38 in
Baguette
Length x width: 11.2 x 5.6 mm
In inches: 0.44 x 0.22 in

3 carat garnet 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
Garnet (this page)
Round, 3 carat: 9.0 mm

3 carat garnet on a finger

9.0 mm
9.0 mm stone on a 16.5 mm finger: it covers 54% of the widthA round 3 carat garnet on a size 6 finger.
4
Finger width: 14.9 mm
Round covers: 60%
Oval covers: 52%
5
Finger width: 15.7 mm
Round covers: 57%
Oval covers: 49%
6
Finger width: 16.5 mm
Round covers: 54%
Oval covers: 46%
7
Finger width: 17.3 mm
Round covers: 52%
Oval covers: 44%
8
Finger width: 18.1 mm
Round covers: 50%
Oval covers: 42%
9
Finger width: 18.9 mm
Round covers: 47%
Oval covers: 40%

Garnet at nearby weights

2 carat garnet
Round diameter: 7.9 mm
3 ct (this page)
Round diameter: 9.0 mm
4 carat garnet
Round diameter: 9.9 mm

Questions

A round 3 carat garnet is about 9.0 mm across. Other shapes are longer than they are wide: an oval is 11.2 x 7.7 mm.
No. A round 3 carat garnet is 3% narrower than a 3 carat diamond (9.3 mm).
0.60 grams. A carat is 200 milligrams for every gem.
A round 3 carat garnet covers 54% 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