18ct Diaspore (Trillion, 20.22×20.22mm, Light Yellowish Green) vs 18ct Alexandrite (Trillion, 19.61×19.61mm, Bluish Green)
Quick summary: When looked from above (face-up position), 18ct Diaspore (20.22×20.22mm, trillion cut) appears 6% larger than 18ct Alexandrite (19.61×19.61mm, trillion cut). See below how they compare side-by-side on a ring and finger.
| 18ct Diaspore (trillion cut) |
vs
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18ct Alexandrite (trillion cut) |
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light yellowish green |
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| 20.22×20.22 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 Diaspore Trillion (20.22×20.22mm, Light Yellowish Green)
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 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.
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 Diaspore (Trillion) | 18 Ct Alexandrite (Trillion) | |
| 20.22×20.22 mm | vs | 19.61×19.61 mm |
| 253.49 mm² | 238.42 mm² |
| 18ct Diaspore Trillion (20.22×20.22mm) | |
| 18ct Alexandrite Trillion (19.61×19.61mm) | |
| Difference: 6% (15.07 mm²) |
18ct Diaspore (Trillion, 20.22×20.22mm) has approx. 6% more face-up area than 18ct Alexandrite (Trillion, 19.61×19.61mm).
Popular comparisons:
- 1ct Diaspore (Trillion, Light Yellowish Green, 7.42 x 7.42) vs. 0.75ct Spinel (Pear, Red, 7.82 x 4.71)
- 1ct Diaspore (Trillion, Light Yellowish Green, 7.42 x 7.42) vs. 1ct Alexandrite (Emerald, Bluish Green, 6.55 x 4.85)
- 1ct Diaspore (Trillion, Light Yellowish Green, 7.42 x 7.42) vs. 1ct Alexandrite (Oval, Bluish Green, 7.77 x 5.18)
- 1ct Diaspore (Trillion, Dark Red, 7.42 x 7.42) vs. 1ct Diopside (Trillion, Black, 7.49 x 7.49)
- 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)