×
carat vs. color  length*  width*
  ×

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

4.2ct Diamond (Cushion, 9.4×9.4mm, White) vs 1ct Tanzanite (Round, 6.37×6.37mm, Light Blue)


Quick summary: When looked from above (face-up position), 4.2ct Diamond (9.4×9.4mm, cushion cut) appears 2.5 times larger than 1ct Tanzanite (6.37×6.37mm, round cut). See below how they compare side-by-side on a ring and finger.

4.2ct Diamond (cushion cut)
vs
 1ct Tanzanite (round cut)
white
 
light blue
9.4×9.4 mm 6.37×6.37 mm
actual size
Actual size of 4.2ct Diamond (cushion cut, 9.4×9.4mm, White color)   Actual size of 1ct Tanzanite (round cut, 6.37×6.37mm, Light Blue color)
 
Actual size is set for screen
Ring: Skin tone:
Ring width: 3.0 mm
Left finger image
Ring on left finger
White 4.2ct Diamond (cushion cut, 9.4×9.4mm) on a left ring and finger
64 mm
Right finger image
Ring on a right finger
Light Blue 1ct Tanzanite (round cut, 6.37×6.37mm) 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
 56% vs 38%
Saved...
Ring diameter: 16.9 mm
USA UK Asia EU1 EU2
Actual sizes of 4.2ct Diamond Cushion (9.4×9.4mm, White) and 1ct Tanzanite Round (6.37×6.37mm, Light Blue) 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, Diamond will face-up smaller than Tanzanite for a given carat weight, because it has higher specific gravity (3.52 vs. 3.35 - this means it's "heavier" compared to Tanzanite 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.


4.2 Ct Diamond (Cushion) 1 Ct Tanzanite (Round)
9.4×9.4 mm vs 6.37×6.37 mm
79.52 mm²   31.87 mm²
Face-up size outline for 4.2ct Diamond (9.4×9.4mm, cushion cut)
Face-up size outline for 1ct Tanzanite (6.37×6.37mm, round cut)
4.2ct Diamond Cushion (9.4×9.4mm)
1ct Tanzanite Round (6.37×6.37mm)
Difference: 150% (47.65 mm²)
4.2ct Diamond (Cushion, 9.4×9.4mm) has approx. 150% more face-up area than 1ct Tanzanite (Round, 6.37×6.37mm). In other words, it's 2.5x larger.


Popular comparisons: