carat vs. color  length*  width*

(or examine a single gem)
* size in mm (optional)

2 Ct Topaz (Round)


1.65 Ct Sapphire (Emerald)

light bluish green
7.85×7.85 mm 7.8×5.0 mm
actual size
Actual size of 2ct Topaz   Actual size of 1.65ct Sapphire
Actual size is set for screen Change
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Light Bluish Green 2ct Topaz on a ring
64 mm
Right finger image
Ring on a right finger
Blue 1.65ct Sapphire on a ring
Your settings
Skin tone
Ring diameter
16.9 mm
Ring width
3.0 mm
Finger length
64 mm
Ring diameter: 16.9 mm
Actual sizes of 2ct Topaz Round (7.85×7.85mm, Light Bluish Green) and 1.65ct Sapphire Emerald (7.8×5.0mm, Blue) as they would appear on a ring and finger. Adjust the ring and finger size to get an idea of how these gemstones would look on your finger.

Where to buy?

JamesAllen → high-quality blue Sapphires, high-end jewelry and competitive prices. Highly recommended.
Amazon → usually offers a good selection from many different vendors. Worth a check.

Face-up Size

All things being equal, Sapphire will face-up smaller than Topaz for a given carat weight, because it has higher specific gravity (4 vs. 3.53 - this means it's "heavier" compared to Topaz of the same size). Face-up size also depends heavily on the proportions of the cut.

Face-up area is a measure of the size of the gem when viewed from above (as set in a ring). It tells you how big the gem is at the girdle plane.

2 Ct Topaz (Round) 1.65 Ct Sapphire (Emerald)
7.85×7.85 mm vs 7.8×5.0 mm
48.4 mm²   36.27 mm²
Face-up size outline
Face-up size outline
2ct Topaz Round (7.85×7.85mm)
1.65ct Sapphire Emerald (7.8×5.0mm)
Difference: 33% (12.13 mm²)
2ct Topaz Round (7.85×7.85mm) has approx. 33% more face-up area than 1.65ct Sapphire Emerald (7.8×5.0mm).

Popular comparisons:

Enter your screen size (diagonal)

My screen size is  inches

Actual size is currently adjusted to screen.

If your screen (phone, tablet, or monitor) is not in diagonal, then the actual size of a gem, ring and finger will not be shown correctly.