Carat vs. Color  Length*  Width*

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

4 Ct Amethyst (Cushion)

versus image

4 Ct Quartz (Round)

Yellowish Green
10.18×10.18 mm 10.89×10.89 mm
Actual size of 4ct Amethyst
Actual size of 4ct Quartz

x Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Purple 4ct Amethyst on a ring
64 mm
Right finger image
Ring on a right finger
Yellowish Green 4ct Quartz 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, Purple) and 4ct Quartz Round (10.89×10.89mm, Yellowish 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.

Face-up Size

Amethyst and Quartz have the same specific gravity so their face-up size depends on the weight, shape and 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 Quartz (Round)
10.18×10.18 mm → 93.27 mm² vs. 93.14 mm² ← 10.89×10.89 mm
Face-up size outline
Face-up size outline
4ct Amethyst Cushion (10.18×10.18mm)
4ct Quartz Round (10.89×10.89mm)
Difference: 0.1% (0.13 mm²)
4ct Amethyst Cushion (10.18×10.18mm) has approx. 0.1% more face-up area than 4ct Quartz Round (10.89×10.89mm).

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