×
carat vs. color  length*  width*
  ×

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

30 Carat Ruby (Cushion, 17.2×17.2mm, Red)

Color:
red
actual size
30ct Ruby displayed at actual size of 17.2×17.2mm, (Cushion cut, Red
Actual size is set for screen


How big is a 30 carat cushion-cut Ruby?

It depends on the cut parameters and length-to-width ratio, but a typical size of a 30ct square cushion-cut Ruby would be around 17.2×17.2 mm (±6%). Check how big it looks on a ring and finger. 
Ring:
Skin tone:
Ring width: 3.0 mm
Saved...
Finger image
Ring on finger
Red 30ct Ruby (cushion cut) shown in real-world size of 17.2×17.2mm on a ring and finger
64 mm
Your settings
Ring
Gold
Skin tone
Light
Ring diameter
16.9 mm
Ring width
3.0 mm
Finger length
64 mm
Finger coverage
102 %
Saved...
Ring diameter: 16.9 mm
USA UK Asia EU1 EU2

Additional Info

Ruby is a red to pink variety of the mineral Corundum. Its name comes from the Latin word "ruber", which simply means "red". Most Rubies on the market are heat-treated to enhance their color and clarity.

Where to buy?
For certified gemstones, high-end gemstone jewelry, and birthstone jewelry, see Blue Nile

Gem Details

Name:
Ruby
Mineral Group:
Corundum
Shape:
Cushion
Chemical Formula:
Al2O3
Crystal Structure:
Hexagonal
Hardness:
9
Specific Gravity
4
Carat weight:
30 ct
Gram weight:
6 g (0.2116 ounces)
Points:
3000 pts
Length:
17.2 mm
Width:
17.2 mm
Est. face-up size:
266.26 mm²
Volume:
1500 mm³
Length-to-width ratio:
1
Refractive Index:
1.76 - 1.77
Luster:
Vitreous to adamantine
Wearability:
Excellent
Care Instructions:
No special or unusual care
Color:
Ruby can be found in the following colors:
Color Light RedColor RedColor Dark Red
Birthstone:
Ruby is a birthstone for the month of July

Popular comparisons: