carat vs. color  length*  width*

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

1 Ct Tanzanite (Round)


0.2 Ct Diamond (Oval)

6.37×6.37 mm 4.74×3.16 mm
actual size
Actual size of 1ct Tanzanite   Actual size of 0.2ct Diamond
Actual size is set for screen Change
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Blue 1ct Tanzanite on a ring
64 mm
Right finger image
Ring on a right finger
Blue 0.2ct Diamond 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 1ct Tanzanite Round (6.37×6.37mm, Blue) and 0.2ct Diamond Oval (4.74×3.16mm, 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 Diamonds, 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, Diamond will face-up smaller than Tanzanite for a given carat weight, because it has higher specific gravity (3.52 vs. 3.3 - this means it's "heavier" compared to Tanzanite 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.

1 Ct Tanzanite (Round) 0.2 Ct Diamond (Oval)
6.37×6.37 mm vs 4.74×3.16 mm
31.87 mm²   12.28 mm²
Face-up size outline
Face-up size outline
1ct Tanzanite Round (6.37×6.37mm)
0.2ct Diamond Oval (4.74×3.16mm)
Difference: 160% (19.59 mm²)
1ct Tanzanite Round (6.37×6.37mm) has approx. 160% more face-up area than 0.2ct Diamond Oval (4.74×3.16mm).

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.