carat vs. color  length*  width*

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

0.3 Ct Tourmaline (Round)


0.4 Ct Tourmaline (Round)

light green
light green
4.36×4.36 mm 4.8×4.8 mm
actual size
Actual size of 0.3ct Tourmaline   Actual size of 0.4ct Tourmaline
Actual size is set for screen Change
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Light Green  0.3ct Tourmaline on a ring
64 mm
Right finger image
Ring on a right finger
Light Green  0.4ct Tourmaline 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 0.3ct Tourmaline Round (4.36×4.36mm, Light Green ) and 0.4ct Tourmaline Round (4.8×4.8mm, Light Green ) 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?

For Tourmaline check what Amazon has to offer. You'll usually find quite a selection from many different vendors. Worth a check. For other high quality gemstones (Rubies, Saphhires, Emeralds) and especially Diamonds, I highly recommend JamesAllen.

Face-up Size

The face-up size depends on the shape of the gem, its weight and 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.

0.3 Ct Tourmaline (Round) 0.4 Ct Tourmaline (Round)
4.36×4.36 mm vs 4.8×4.8 mm
14.93 mm²   18.1 mm²
Face-up size outline
Face-up size outline
0.3ct Tourmaline Round (4.36×4.36mm)
0.4ct Tourmaline Round (4.8×4.8mm)
Difference: 21% (3.17 mm²)
0.4ct Tourmaline Round (4.8×4.8mm) has approx. 21% more face-up area than 0.3ct Tourmaline Round (4.36×4.36mm).

Popular comparisons:

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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.