28ct Alexandrite (Radiant, 17.12×17.12mm, Bluish Green) vs 28ct Topaz (Radiant, 17.44×17.44mm, Blue)
Quick summary: When looked from above (face-up position), 28ct Topaz (17.44×17.44mm, radiant cut) appears 4% larger than 28ct Alexandrite (17.12×17.12mm, radiant cut). See below how they compare side-by-side on a ring and finger.
| 28ct Alexandrite (radiant cut) |
vs
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28ct Topaz (radiant cut) |
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bluish green |
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| 17.12×17.12 mm | 17.44×17.44 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
28ct Alexandrite Radiant (17.12×17.12mm, Bluish Green)
and
28ct Topaz Radiant (17.44×17.44mm, 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.
| 28 Ct Alexandrite (Radiant) | 28 Ct Topaz (Radiant) | |
| 17.12×17.12 mm | vs | 17.44×17.44 mm |
| 278.44 mm² | 288.95 mm² |
| 28ct Alexandrite Radiant (17.12×17.12mm) | |
| 28ct Topaz Radiant (17.44×17.44mm) | |
| Difference: 4% (10.51 mm²) |
28ct Topaz (Radiant, 17.44×17.44mm) has approx. 4% more face-up area than 28ct Alexandrite (Radiant, 17.12×17.12mm).
Popular comparisons:
- 2.7ct Ruby (Pear, Red, 10 x 7) vs. 3ct Ruby (Emerald, Red, 9 x 7)
- 1.5ct Tourmaline (Round, Light Red, 7.45 x 7.45) vs. 1.5ct Sapphire (Round, Light Blue, 6.84 x 6.84)
- 1ct Kyanite (Oval, Blue, 7.77 x 5.18) vs. 1ct Tanzanite (Oval, Blue, 8.07 x 5.38)
- 1ct Aquamarine (Oval, Light Blue, 8 x 6) vs. 1ct Spinel (Oval, Gray, 8 x 6)
- 1.16ct Diamond (Round, White, 6.82 x 6.85) vs. 1.2ct Diamond (Round, White, 6.82 x 6.86)
- 6ct Morganite (Cushion, Light Red, 12 x 10) vs. 3.5ct Sapphire (Cushion, Blue, 8.49 x 8.49)
- 1ct Sapphire (Baguette, Blue, 6.93 x 4.62) vs. 1ct Emerald (Emerald, Green, 7.28 x 5.39)
- 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)