30ct Alexandrite (Heart, 19.9×19.9mm, Bluish Green) vs 30ct Topaz (Heart, 20.27×20.27mm, Blue)
Quick summary: When looked from above (face-up position), 30ct Topaz (20.27×20.27mm, heart cut) appears 4% larger than 30ct Alexandrite (19.9×19.9mm, heart cut). See below how they compare side-by-side on a ring and finger.
| 30ct Alexandrite (heart cut) |
vs
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30ct Topaz (heart cut) |
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bluish green |
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| 19.9×19.9 mm | 20.27×20.27 mm | |
| actual size | ||
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Actual size is set for screen
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Ring:
Skin tone:
Ring width: 3.0 mm
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64 mm |
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Actual sizes of
30ct Alexandrite Heart (19.9×19.9mm, Bluish Green)
and
30ct Topaz Heart (20.27×20.27mm, 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.
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 (Heart) | 30 Ct Topaz (Heart) | |
| 19.9×19.9 mm | vs | 20.27×20.27 mm |
| 285.13 mm² | 295.83 mm² |
| 30ct Alexandrite Heart (19.9×19.9mm) | |
| 30ct Topaz Heart (20.27×20.27mm) | |
| Difference: 4% (10.7 mm²) |
30ct Topaz (Heart, 20.27×20.27mm) has approx. 4% more face-up area than 30ct Alexandrite (Heart, 19.9×19.9mm).
Popular comparisons:
- 2.7ct Ruby (Pear, Red, 10 x 7) vs. 3ct Ruby (Emerald, Red, 9 x 7)
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- 1ct Topaz (Round, Blue, 6 x 6) vs. 0.5ct Topaz (Round, Blue, 5 x 5)
- 2ct Zircon (Round, Light Orange, 7.16 x 7.16) vs. 2ct Emerald (Emerald, Dark Green, 9.17 x 6.79)