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30ct Alexandrite (Round, 19.01×19.01mm, Bluish Green) vs 30ct Topaz (Round, 19.37×19.37mm, Blue)


Quick summary: When looked from above (face-up position), 30ct Topaz (19.37×19.37mm, round cut) appears 4% larger than 30ct Alexandrite (19.01×19.01mm, round cut). See below how they compare side-by-side on a ring and finger.

30ct Alexandrite (round cut)
vs
 30ct Topaz (round cut)
bluish green
 
blue
19.01×19.01 mm 19.37×19.37 mm
actual size
Actual size of 30ct Alexandrite (round cut, 19.01×19.01mm, Bluish Green color)   Actual size of 30ct Topaz (round cut, 19.37×19.37mm, Blue color)
 
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Bluish Green 30ct Alexandrite (round cut, 19.01×19.01mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
Blue 30ct Topaz (round cut, 19.37×19.37mm) 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
 113% vs 115%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 30ct Alexandrite Round (19.01×19.01mm, Bluish Green) and 30ct Topaz Round (19.37×19.37mm, 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?

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 Topaz for a given carat weight, because it has higher specific gravity (3.73 vs. 3.53 - this means it's "heavier" compared to Topaz 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 Alexandrite (Round) 30 Ct Topaz (Round)
19.01×19.01 mm vs 19.37×19.37 mm
283.83 mm²   294.68 mm²
Face-up size outline for 30ct Topaz (19.37×19.37mm, round cut)
Face-up size outline for 30ct Alexandrite (19.01×19.01mm, round cut)
30ct Alexandrite Round (19.01×19.01mm)
30ct Topaz Round (19.37×19.37mm)
Difference: 4% (10.85 mm²)
30ct Topaz (Round, 19.37×19.37mm) has approx. 4% more face-up area than 30ct Alexandrite (Round, 19.01×19.01mm).


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