How big is a 3 carat zircon?

By HeyGema™ · Updated

In short

A 3 carat round zircon measures about 8.5 mm across (0.33 inches), 9% narrower than a 3 carat diamond (9.3 mm). An oval of the same weight is 10.5 x 7.2 mm and an emerald cut 9.2 x 6.6 mm.

Carat to mm calculator

About 8.5 x 8.5 mm

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

Round
8.5 mm
Oval
10.5 x 7.2 mm
Cushion
7.3 x 7.3 mm
Princess
7.2 x 7.2 mm
Emerald cut
9.2 x 6.6 mm
Asscher
7.2 x 7.2 mm
Radiant
8.5 x 6.6 mm
Pear
11.1 x 7.2 mm
Marquise
13.6 x 6.8 mm
Heart
8.5 x 8.5 mm
Trillion
9.2 x 9.2 mm
Baguette
10.5 x 5.2 mm
= 5 mm in every picture above
A 3 carat zircon in 12 shapes, drawn to one scale.

3 carat zircon size by shape

Face-up measurements of a well-cut 3 carat zircon. Zircon is denser than diamond (4.69 against 3.52), so it packs more weight into less space and faces up 9% narrower for the same weight.

Round
Length x width: 8.5 mm
In inches: 0.33 in
Oval
Length x width: 10.5 x 7.2 mm
In inches: 0.41 x 0.28 in
Cushion
Length x width: 7.3 x 7.3 mm
In inches: 0.29 x 0.29 in
Princess
Length x width: 7.2 x 7.2 mm
In inches: 0.28 x 0.28 in
Emerald cut
Length x width: 9.2 x 6.6 mm
In inches: 0.36 x 0.26 in
Asscher
Length x width: 7.2 x 7.2 mm
In inches: 0.28 x 0.28 in
Radiant
Length x width: 8.5 x 6.6 mm
In inches: 0.34 x 0.26 in
Pear
Length x width: 11.1 x 7.2 mm
In inches: 0.44 x 0.28 in
Marquise
Length x width: 13.6 x 6.8 mm
In inches: 0.54 x 0.27 in
Heart
Length x width: 8.5 x 8.5 mm
In inches: 0.34 x 0.34 in
Trillion
Length x width: 9.2 x 9.2 mm
In inches: 0.36 x 0.36 in
Baguette
Length x width: 10.5 x 5.2 mm
In inches: 0.41 x 0.21 in

3 carat zircon 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
Zircon (this page)
Round, 3 carat: 8.5 mm

3 carat zircon on a finger

8.5 mm
8.5 mm stone on a 16.5 mm finger: it covers 51% of the widthA round 3 carat zircon on a size 6 finger.
4
Finger width: 14.9 mm
Round covers: 57%
Oval covers: 48%
5
Finger width: 15.7 mm
Round covers: 54%
Oval covers: 46%
6
Finger width: 16.5 mm
Round covers: 51%
Oval covers: 44%
7
Finger width: 17.3 mm
Round covers: 49%
Oval covers: 42%
8
Finger width: 18.1 mm
Round covers: 47%
Oval covers: 40%
9
Finger width: 18.9 mm
Round covers: 45%
Oval covers: 38%

Zircon at nearby weights

2 carat zircon
Round diameter: 7.4 mm
3 ct (this page)
Round diameter: 8.5 mm
4 carat zircon
Round diameter: 9.3 mm

Questions

A round 3 carat zircon is about 8.5 mm across. Other shapes are longer than they are wide: an oval is 10.5 x 7.2 mm.
No. A round 3 carat zircon is 9% narrower than a 3 carat diamond (9.3 mm).
0.60 grams. A carat is 200 milligrams for every gem.
A round 3 carat zircon covers 51% 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