How big is a 4 carat tanzanite?
By HeyGema™ · Updated
In short
A 4 carat round tanzanite measures about 10.4 mm across (0.41 inches), 2% wider than a 4 carat diamond (10.2 mm). An oval of the same weight is 12.9 x 8.9 mm and an emerald cut 11.3 x 8.1 mm.
- 10.4 mmround tanzanite, across
- 0.41 inthe same in inches
- 0.80 gweight
- 63%of a size 6 finger's width
Carat to mm calculator
About 10.4 x 10.4 mm
An estimate for a well-cut stone. A deep or shallow cut faces up smaller or bigger.
Round
10.4 mm
Oval
12.9 x 8.9 mm
Cushion
9.0 x 9.0 mm
Princess
8.9 x 8.9 mm
Emerald cut
11.3 x 8.1 mm
Asscher
8.9 x 8.9 mm
Radiant
10.5 x 8.1 mm
Pear
13.7 x 8.9 mm
Marquise
16.8 x 8.4 mm
Heart
10.5 x 10.5 mm
Trillion
11.3 x 11.3 mm
Baguette
12.9 x 6.5 mm
= 5 mm in every picture above
4 carat tanzanite size by shape
Face-up measurements of a well-cut 4 carat tanzanite. Tanzanite is lighter than diamond (3.35 against 3.52), so the same weight gives a bigger stone, 2% wider across.
- Round
- Length x width: 10.4 mm
- In inches: 0.41 in
- Oval
- Length x width: 12.9 x 8.9 mm
- In inches: 0.51 x 0.35 in
- Cushion
- Length x width: 9.0 x 9.0 mm
- In inches: 0.36 x 0.36 in
- Princess
- Length x width: 8.9 x 8.9 mm
- In inches: 0.35 x 0.35 in
- Emerald cut
- Length x width: 11.3 x 8.1 mm
- In inches: 0.44 x 0.32 in
- Asscher
- Length x width: 8.9 x 8.9 mm
- In inches: 0.35 x 0.35 in
- Radiant
- Length x width: 10.5 x 8.1 mm
- In inches: 0.41 x 0.32 in
- Pear
- Length x width: 13.7 x 8.9 mm
- In inches: 0.54 x 0.35 in
- Marquise
- Length x width: 16.8 x 8.4 mm
- In inches: 0.66 x 0.33 in
- Heart
- Length x width: 10.5 x 10.5 mm
- In inches: 0.41 x 0.41 in
- Trillion
- Length x width: 11.3 x 11.3 mm
- In inches: 0.44 x 0.44 in
- Baguette
- Length x width: 12.9 x 6.5 mm
- In inches: 0.51 x 0.25 in
4 carat tanzanite 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
- Topaz
- Round, 4 carat: 10.2 mm
- Tanzanite (this page)
- Round, 4 carat: 10.4 mm
4 carat tanzanite on a finger
- 4
- Finger width: 14.9 mm
- Round covers: 70%
- Oval covers: 60%
- 5
- Finger width: 15.7 mm
- Round covers: 66%
- Oval covers: 57%
- 6
- Finger width: 16.5 mm
- Round covers: 63%
- Oval covers: 54%
- 7
- Finger width: 17.3 mm
- Round covers: 60%
- Oval covers: 51%
- 8
- Finger width: 18.1 mm
- Round covers: 57%
- Oval covers: 49%
- 9
- Finger width: 18.9 mm
- Round covers: 55%
- Oval covers: 47%
Tanzanite at nearby weights
- 3 carat tanzanite
- Round diameter: 9.5 mm
- 4 ct (this page)
- Round diameter: 10.4 mm
- 5 carat tanzanite
- Round diameter: 11.2 mm
Questions
A round 4 carat tanzanite is about 10.4 mm across. Other shapes are longer than they are wide: an oval is 12.9 x 8.9 mm.
Yes. A round 4 carat tanzanite is 2% wider than a 4 carat diamond (10.2 mm).
0.80 grams. A carat is 200 milligrams for every gem.
A round 4 carat tanzanite covers 63% of the width of a size 6 finger. Compare it with a ring you have tried on in the finger chart above.