18ct Tourmaline (Round, 17.13×17.13mm, Purple) vs 18ct Quartz (Round, 17.97×17.97mm, Brown)
Quick summary: When looked from above (face-up position), 18ct Quartz (17.97×17.97mm, round cut) appears 10% larger than 18ct Tourmaline (17.13×17.13mm, round cut). See below how they compare side-by-side on a ring and finger.
| 18ct Tourmaline (round cut) |
vs
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18ct Quartz (round cut) |
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purple |
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| 17.13×17.13 mm | 17.97×17.97 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 Tourmaline Round (17.13×17.13mm, Purple)
and
18ct Quartz Round (17.97×17.97mm, Brown)
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, Tourmaline will face-up smaller than Quartz for a given
carat weight, because it has higher specific gravity
(3.06 vs. 2.65 - this means it's "heavier" compared to Quartz 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 Tourmaline (Round) | 18 Ct Quartz (Round) | |
| 17.13×17.13 mm | vs | 17.97×17.97 mm |
| 230.46 mm² | 253.62 mm² |
| 18ct Tourmaline Round (17.13×17.13mm) | |
| 18ct Quartz Round (17.97×17.97mm) | |
| Difference: 10% (23.16 mm²) |
18ct Quartz (Round, 17.97×17.97mm) has approx. 10% more face-up area than 18ct Tourmaline (Round, 17.13×17.13mm).
Popular comparisons:
- 1ct Tourmaline (Round, Light Green , 6.51 x 6.51) vs. 1ct Diamond (Round, White, 6.5 x 6.5)
- 1.5ct Tourmaline (Round, Light Red, 7.45 x 7.45) vs. 1.5ct Sapphire (Round, Light Blue, 6.84 x 6.84)
- 2ct Tourmaline (Round, Violet, 8.2 x 8.2) vs. 2ct Tourmaline (Oval, Violet, 10.38 x 6.92)
- 1ct Tourmaline (Round, Violet, 6.51 x 6.51) vs. 1ct Diamond (Round, White, 6.5 x 6.5)
- 0.32ct Tourmaline (Round, Green, 4.45 x 4.45) vs. 0.3ct Sapphire (Round, Green, 4 x 4)
- 1.41ct Tourmaline (Round, Light Red, 7.3 x 7.3) vs. 1.58ct Tourmaline (Round, Light Red, 7.58 x 7.58)
- 0.3ct Tourmaline (Round, Violet, 4.36 x 4.36) vs. 1ct Emerald (Emerald, Green, 7.28 x 5.39)
- 2ct Tourmaline (Round, Violet, 8.2 x 8.2) vs. 2ct Diamond (Round, White, 8.19 x 8.19)
- 0.09ct Tourmaline (Round, Bluish Green, 2.81 x 2.81) vs. 0.09ct Diamond (Round, White, 2.81 x 2.81)