18ct Ruby (Cushion, 14.51×14.51mm, Red) vs 3ct Diamond (Cushion, 8.4×8.4mm, White)
Quick summary: When looked from above (face-up position), 18ct Ruby (14.51×14.51mm, cushion cut) appears 3 times larger than 3ct Diamond (8.4×8.4mm, cushion cut). See below how they compare side-by-side on a ring and finger.
| 18ct Ruby (cushion cut) |
vs
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3ct Diamond (cushion cut) |
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red |
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| 14.51×14.51 mm | 8.4×8.4 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 Ruby Cushion (14.51×14.51mm, Red)
and
3ct Diamond Cushion (8.4×8.4mm, White)
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, Ruby will face-up smaller than Diamond for a given
carat weight, because it has higher specific gravity
(4 vs. 3.52 - this means it's "heavier" compared to Diamond 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 Ruby (Cushion) | 3 Ct Diamond (Cushion) | |
| 14.51×14.51 mm | vs | 8.4×8.4 mm |
| 189.49 mm² | 63.5 mm² |
| 18ct Ruby Cushion (14.51×14.51mm) | |
| 3ct Diamond Cushion (8.4×8.4mm) | |
| Difference: 198% (125.99 mm²) |
18ct Ruby (Cushion, 14.51×14.51mm) has approx. 198% more face-up area than 3ct Diamond (Cushion, 8.4×8.4mm). In other words, it's 2.98x larger.
Popular comparisons:
- 18ct Ruby (Cushion, Red, 14.51 x 14.51) vs. 40ct Spinel (Emerald, Blue, 22.61 x 16.75)
- 18ct Ruby (Cushion, Red, 14.51 x 14.51) vs. 40ct Spinel (Cushion, Blue, 19.61 x 19.61)
- 0.45ct Ruby (Cushion, Red, 4.28 x 4.28) vs. 0.33ct Sapphire (Trillion, Blue, 4.86 x 4.86)
- 3.45ct Ruby (Cushion, Red, 8.45 x 8.45) vs. 1ct Emerald (Cushion, Green, 6.37 x 6.37)
- 3ct Ruby (Cushion, Red, 8.06 x 8.06) vs. 5ct Ruby (Round, Red, 10.22 x 10.22)
- 3ct Ruby (Cushion, Red, 8.06 x 8.06) vs. 5ct Ruby (Cushion, Red, 9.56 x 9.56)
- 3ct Ruby (Cushion, Red, 8.06 x 8.06) vs. 3ct Diamond (Round, White, 9.37 x 9.37)
- 1ct Ruby (Cushion, Red, 5.59 x 5.59) vs. 1ct Emerald (Emerald, Green, 7.28 x 5.39)