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30ct Diaspore (Cushion, 18.16×18.16mm, Light Yellowish Green) vs 30ct Alexandrite (Cushion, 17.61×17.61mm, Bluish Green)


Quick summary: When looked from above (face-up position), 30ct Diaspore (18.16×18.16mm, cushion cut) appears 6% larger than 30ct Alexandrite (17.61×17.61mm, cushion cut). See below how they compare side-by-side on a ring and finger.

30ct Diaspore (cushion cut)
vs
 30ct Alexandrite (cushion cut)
light yellowish green
 
bluish green
18.16×18.16 mm 17.61×17.61 mm
actual size
Actual size of 30ct Diaspore (cushion cut, 18.16×18.16mm, Light Yellowish Green color)   Actual size of 30ct Alexandrite (cushion cut, 17.61×17.61mm, Bluish Green color)
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Light Yellowish Green 30ct Diaspore (cushion cut, 18.16×18.16mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
Bluish Green 30ct Alexandrite (cushion cut, 17.61×17.61mm) on a right ring and finger
Your settings
Ring
 Gold
Skin tone
 Light
Ring diameter
 16.9 mm
Ring width
 3.0 mm
Finger length
 64 mm
Finger coverage
 108% vs 105%
Saved...
Ring diameter: 16.9 mm
USA UK Asia EU1 EU2
Actual sizes of 30ct Diaspore Cushion (18.16×18.16mm, Light Yellowish Green) and 30ct Alexandrite Cushion (17.61×17.61mm, Bluish 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 certified gemstones, high-end gemstone jewelry, and birthstone jewelry, see Blue Nile

Face-up Size

All things being equal, Alexandrite will face-up smaller than Diaspore for a given carat weight, because it has higher specific gravity (3.73 vs. 3.4 - this means it's "heavier" compared to Diaspore 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.


30 Ct Diaspore (Cushion) 30 Ct Alexandrite (Cushion)
18.16×18.16 mm vs 17.61×17.61 mm
296.81 mm²   279.1 mm²
Face-up size outline for 30ct Diaspore (18.16×18.16mm, cushion cut)
Face-up size outline for 30ct Alexandrite (17.61×17.61mm, cushion cut)
30ct Diaspore Cushion (18.16×18.16mm)
30ct Alexandrite Cushion (17.61×17.61mm)
Difference: 6% (17.71 mm²)
30ct Diaspore (Cushion, 18.16×18.16mm) has approx. 6% more face-up area than 30ct Alexandrite (Cushion, 17.61×17.61mm).


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