18ct Amethyst (Trillion, 21.98×21.98mm, Violet) vs 18ct Alexandrite (Trillion, 19.61×19.61mm, Bluish Green)
Quick summary: When looked from above (face-up position), 18ct Amethyst (21.98×21.98mm, trillion cut) appears 26% larger than 18ct Alexandrite (19.61×19.61mm, trillion cut). See below how they compare side-by-side on a ring and finger.
| 18ct Amethyst (trillion cut) |
vs
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18ct Alexandrite (trillion cut) |
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violet |
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| 21.98×21.98 mm | 19.61×19.61 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
18ct Amethyst Trillion (21.98×21.98mm, Violet)
and
18ct Alexandrite Trillion (19.61×19.61mm, 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 Amethyst for a given
carat weight, because it has higher specific gravity
(3.73 vs. 2.65 - this means it's "heavier" compared to Amethyst 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.
| 18 Ct Amethyst (Trillion) | 18 Ct Alexandrite (Trillion) | |
| 21.98×21.98 mm | vs | 19.61×19.61 mm |
| 299.53 mm² | 238.42 mm² |
| 18ct Amethyst Trillion (21.98×21.98mm) | |
| 18ct Alexandrite Trillion (19.61×19.61mm) | |
| Difference: 26% (61.11 mm²) |
18ct Amethyst (Trillion, 21.98×21.98mm) has approx. 26% more face-up area than 18ct Alexandrite (Trillion, 19.61×19.61mm).
Popular comparisons:
- 0.2ct Amethyst (Trillion, Dark Violet, 4.72 x 4.72) vs. 10ct Aquamarine (Baguette, Light Bluish Green, 17.03 x 11.35)
- 0.8ct Amethyst (Trillion, Purple, 7.48 x 7.48) vs. 0.5ct Amethyst (Oval, Purple, 6.89 x 4.59)
- 1ct Amethyst (Trillion, Dark Violet, 8.06 x 8.06) vs. 1ct Sapphire (Emerald, Blue, 6.39 x 4.73)
- 3ct Amethyst (Trillion, Violet, 11.63 x 11.63) vs. 3ct Amethyst (Round, Violet, 9.89 x 9.89)
- 1ct Amethyst (Trillion, Violet, 8.06 x 8.06) vs. 1ct Emerald (Emerald, Green, 7.28 x 5.39)
- 0.8ct Amethyst (Trillion, Purple, 7.48 x 7.48) vs. 0.5ct Amethyst (Trillion, Purple, 6.4 x 6.4)
- 5ct Amethyst (Trillion, Dark Violet, 13.79 x 13.79) vs. 5ct Sapphire (Baguette, Blue, 11.85 x 7.9)
- 0.1ct Amethyst (Trillion, Dark Violet, 3.74 x 3.74) vs. 10ct Aquamarine (Cushion, Light Bluish Green, 13.73 x 13.73)
- 1ct Amethyst (Trillion, Violet, 8.06 x 8.06) vs. 1.47ct Topaz (Trillion, Blue, 8.33 x 8.33)