How big is a 4 carat alexandrite?
By HeyGema™ · Updated
In short
A 4 carat round alexandrite measures about 10.0 mm across (0.40 inches), 2% narrower than a 4 carat diamond (10.2 mm). An oval of the same weight is 12.5 x 8.6 mm and an emerald cut 10.9 x 7.8 mm.
- 10.0 mmround alexandrite, across
- 0.40 inthe same in inches
- 0.80 gweight
- 61%of a size 6 finger's width
Carat to mm calculator
About 10.0 x 10.0 mm
An estimate for a well-cut stone. A deep or shallow cut faces up smaller or bigger.
Round
10.0 mm
Oval
12.5 x 8.6 mm
Cushion
8.7 x 8.7 mm
Princess
8.6 x 8.6 mm
Emerald cut
10.9 x 7.8 mm
Asscher
8.6 x 8.6 mm
Radiant
10.1 x 7.8 mm
Pear
13.2 x 8.6 mm
Marquise
16.2 x 8.1 mm
Heart
10.1 x 10.1 mm
Trillion
10.9 x 10.9 mm
Baguette
12.5 x 6.2 mm
= 5 mm in every picture above
4 carat alexandrite size by shape
Face-up measurements of a well-cut 4 carat alexandrite. Alexandrite is denser than diamond (3.73 against 3.52), so it packs more weight into less space and faces up 2% narrower for the same weight.
- Round
- Length x width: 10.0 mm
- In inches: 0.40 in
- Oval
- Length x width: 12.5 x 8.6 mm
- In inches: 0.49 x 0.34 in
- Cushion
- Length x width: 8.7 x 8.7 mm
- In inches: 0.34 x 0.34 in
- Princess
- Length x width: 8.6 x 8.6 mm
- In inches: 0.34 x 0.34 in
- Emerald cut
- Length x width: 10.9 x 7.8 mm
- In inches: 0.43 x 0.31 in
- Asscher
- Length x width: 8.6 x 8.6 mm
- In inches: 0.34 x 0.34 in
- Radiant
- Length x width: 10.1 x 7.8 mm
- In inches: 0.40 x 0.31 in
- Pear
- Length x width: 13.2 x 8.6 mm
- In inches: 0.52 x 0.34 in
- Marquise
- Length x width: 16.2 x 8.1 mm
- In inches: 0.64 x 0.32 in
- Heart
- Length x width: 10.1 x 10.1 mm
- In inches: 0.40 x 0.40 in
- Trillion
- Length x width: 10.9 x 10.9 mm
- In inches: 0.43 x 0.43 in
- Baguette
- Length x width: 12.5 x 6.2 mm
- In inches: 0.49 x 0.25 in
4 carat alexandrite 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
- Alexandrite (this page)
- Round, 4 carat: 10.0 mm
4 carat alexandrite on a finger
- 4
- Finger width: 14.9 mm
- Round covers: 67%
- Oval covers: 58%
- 5
- Finger width: 15.7 mm
- Round covers: 64%
- Oval covers: 55%
- 6
- Finger width: 16.5 mm
- Round covers: 61%
- Oval covers: 52%
- 7
- Finger width: 17.3 mm
- Round covers: 58%
- Oval covers: 49%
- 8
- Finger width: 18.1 mm
- Round covers: 55%
- Oval covers: 47%
- 9
- Finger width: 18.9 mm
- Round covers: 53%
- Oval covers: 45%
Alexandrite at nearby weights
- 3 carat alexandrite
- Round diameter: 9.1 mm
- 4 ct (this page)
- Round diameter: 10.0 mm
- 5 carat alexandrite
- Round diameter: 10.8 mm
Questions
A round 4 carat alexandrite is about 10.0 mm across. Other shapes are longer than they are wide: an oval is 12.5 x 8.6 mm.
No. A round 4 carat alexandrite is 2% narrower than a 4 carat diamond (10.2 mm).
0.80 grams. A carat is 200 milligrams for every gem.
A round 4 carat alexandrite covers 61% of the width of a size 6 finger. Compare it with a ring you have tried on in the finger chart above.