Round brilliant cut gems carat weight conversions

Round Faceted Gemstone Weight Chart (approximate weights)

4
mm

5
mm

6
mm

6.5
mm

7
mm

8
mm

10
mm

Alexandrite

.35 ct

.63 ct

1.30 ct

1.86 ct

2.15 ct

2.90 ct

5.20 ct

Amethyst

.20 ct

.40 ct

.70 ct

1.10 ct

1.30 ct

1.80 ct

3.30 ct

Aquamarine

.25 ct

.45 ct

.75 ct

1.31 ct

1.60 ct

2.40 ct

3.50 ct

Citrine

.20 ct

.40 ct

.70 ct

1.10 ct

1.30 ct

1.80 ct

3.30 ct

Diamond

.23 ct

.47 ct

.80 ct

1.00 ct

1.25 ct

1.90 ct

3.50 ct

Emerald

.27 ct

.48 ct

.80 ct

1.26 ct

1.70 ct

2.50 ct

6.10 ct

Garnet

.30 ct

.60 ct

1.00 ct

1.40 ct

1.60 ct

2.50 ct

5.75 ct

Opal

.16 ct

.34 ct

.57 ct

.75 ct

.83 ct

1.30 ct

2.00 ct

Peridot

.26 ct

.50 ct

.85 ct

1.11 ct

1.25 ct

2.00 ct

5.25 ct

Ruby

.34 ct

.65 ct

1.05 ct

1.41 ct

1.60 ct

2.25 ct

4.50 ct

Sapphire

.34 ct

.65 ct

1.05 ct

1.41 ct

1.60 ct

2.25 ct

4.50 ct

Topaz

.30 ct

.56 ct

1.00 ct

1.36 ct

1.55 ct

2.50 ct

5.75 ct

Tourmaline

.24 ct

.45 ct

.75 ct

1.28 ct

1.55 ct

2.00 ct

3.00 ct

Zircon

.36 ct

.69 ct

1.25 ct

1.58 ct

1.75 ct

2.60 ct

5.00 ct