Carat vs. Color  Length*  Width*

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4 Ct Amethyst (Cushion)

versus image

4 Ct Diamond (Cushion)

10.18×10.18 mm 9.25×9.25 mm
Actual size of 4ct Amethyst
Actual size of 4ct Diamond

x Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Violet 4ct Amethyst on a ring
64 mm
Right finger image
Ring on a right finger
White 4ct 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 4ct Amethyst Cushion (10.18×10.18mm, Violet) and 4ct Diamond Cushion (9.25×9.25mm, White) 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.

Face-up Size

All things being equal, Diamond will face-up smaller than Amethyst for a given carat weight, because it has higher specific gravity (3.52 vs. 2.65 - this means it's "heavier" compared to Amethyst 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.

4 Ct Amethyst (Cushion) 4 Ct Diamond (Cushion)
10.18×10.18 mm → 93.27 mm² vs. 77.01 mm² ← 9.25×9.25 mm
Face-up size outline
Face-up size outline
4ct Amethyst Cushion (10.18×10.18mm)
4ct Diamond Cushion (9.25×9.25mm)
Difference: 21% (16.26 mm²)
4ct Amethyst Cushion (10.18×10.18mm) has approx. 21% more face-up area than 4ct Diamond Cushion (9.25×9.25mm).

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