×
carat vs. color  length*  width*
  ×

(or examine a )
* size in mm (optional)

18ct Tourmaline (Marquise, 27.86×13.93mm, Purple) vs 18ct Quartz (Marquise, 29.22×14.61mm, Brown)


Quick summary: When looked from above (face-up position), 18ct Quartz (29.22×14.61mm, marquise cut) appears 10% larger than 18ct Tourmaline (27.86×13.93mm, marquise cut). See below how they compare side-by-side on a ring and finger.

18ct Tourmaline (marquise cut)
vs
 18ct Quartz (marquise cut)
purple
 
brown
27.86×13.93 mm 29.22×14.61 mm
actual size
Actual size of 18ct Tourmaline (marquise cut, 27.86×13.93mm, Purple color)   Actual size of 18ct Quartz (marquise cut, 29.22×14.61mm, Brown color)
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
Purple 18ct Tourmaline (marquise cut, 27.86×13.93mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
Brown 18ct Quartz (marquise cut, 29.22×14.61mm) 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
 83% vs 87%
Saved...
Ring diameter: 16.9 mm
USA UK Asia EU1 EU2
Actual sizes of 18ct Tourmaline Marquise (27.86×13.93mm, Purple) and 18ct Quartz Marquise (29.22×14.61mm, 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.


18 Ct Tourmaline (Marquise) 18 Ct Quartz (Marquise)
27.86×13.93 mm vs 29.22×14.61 mm
275.54 mm²   303.1 mm²
Face-up size outline for 18ct Quartz (29.22×14.61mm, marquise cut)
Face-up size outline for 18ct Tourmaline (27.86×13.93mm, marquise cut)
18ct Tourmaline Marquise (27.86×13.93mm)
18ct Quartz Marquise (29.22×14.61mm)
Difference: 10% (27.56 mm²)
18ct Quartz (Marquise, 29.22×14.61mm) has approx. 10% more face-up area than 18ct Tourmaline (Marquise, 27.86×13.93mm).


Popular comparisons: