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18ct Topaz (Cabochon, 18.71×12.47mm, Blue) vs 18ct Quartz (Cabochon, 20.58×13.72mm, Brown)


Quick summary: When looked from above (face-up position), 18ct Quartz (20.58×13.72mm, cabochon cut) appears 21% larger than 18ct Topaz (18.71×12.47mm, cabochon cut). See below how they compare side-by-side on a ring and finger.

18ct Topaz (cabochon cut)
vs
 18ct Quartz (cabochon cut)
blue
 
brown
18.71×12.47 mm 20.58×13.72 mm
actual size
Actual size of 18ct Topaz (cabochon cut, 18.71×12.47mm, Blue color)   Actual size of 18ct Quartz (cabochon cut, 20.58×13.72mm, Brown color)
 
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Blue 18ct Topaz (cabochon cut, 18.71×12.47mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
Brown 18ct Quartz (cabochon cut, 20.58×13.72mm) on a right ring and finger
Your settings
Ring
 Gold
Skin tone
 Light
Ring diameter
 16.9 mm
Ring width
 3.0 mm
Finger length
 64 mm
Finger coverage
 74% vs 82%
Saved...
Ring diameter: 16.9 mm
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Actual sizes of 18ct Topaz Cabochon (18.71×12.47mm, Blue) and 18ct Quartz Cabochon (20.58×13.72mm, 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, Topaz will face-up smaller than Quartz for a given carat weight, because it has higher specific gravity (3.53 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.


18 Ct Topaz (Cabochon) 18 Ct Quartz (Cabochon)
18.71×12.47 mm vs 20.58×13.72 mm
191.32 mm²   231.53 mm²
Face-up size outline for 18ct Quartz (20.58×13.72mm, cabochon cut)
Face-up size outline for 18ct Topaz (18.71×12.47mm, cabochon cut)
18ct Topaz Cabochon (18.71×12.47mm)
18ct Quartz Cabochon (20.58×13.72mm)
Difference: 21% (40.21 mm²)
18ct Quartz (Cabochon, 20.58×13.72mm) has approx. 21% more face-up area than 18ct Topaz (Cabochon, 18.71×12.47mm).


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