1.25 Carat Ruby (Princess, 5.66×5.66mm, Red)

Color:

red

actual size

Actual size is set for screen

How big is a 1.25 carat princess-cut Ruby?

It depends on the cut parameters, but a typical size of a 1.25ct princess-cut Ruby would be around 5.66×5.66 mm (±6%). You can check how big it looks on a ring and finger below.

Ring:

Gold
Platinum

Skin tone:

Pale
Light
Medium
Dark

Ring width: 3.0 mm

Saved...

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	34 %

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:	Princess
Chemical Formula:	Al₂O₃
Crystal Structure:	Hexagonal
Hardness:	9
Specific Gravity	4
Carat weight:	1.25 ct
Gram weight:	0.25 g (0.0088 ounces)
Points:	125 pts
Length:	5.66 mm
Width:	5.66 mm
Est. face-up size:	32.04 mm²
Volume:	62.5 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:
Birthstone:	Ruby is a birthstone for the month of July

Popular comparisons:

About Ruby Specific Gravity

Ruby has a specific gravity of approximately 3.95 - 4.05, with 4 being a generally accepted standard average for gem-quality material.

For all the Ruby size calculations on this website, the specific gravity of 4 is used.

To learn more about it and why it matters, and to compare densities of all the gemstones on one page, click here.

Ring & Finger Simulator

Use the simulator on this page to play around with different ring and finger configurations.

To select a different gemstone, shape, color or size, or to compare two gems side-by-side, use the form at the top of the page. Comparison example: 1.25ct Ruby vs Spinel (Princess Cut)

If you want to compare princess-cut Ruby sizes from 0.25 to 40ct on one page, see Princess Cut Ruby Size Chart

In order to view real-world sizes on your screen, ensure that the actual size is set to your device screen size (diagonal in inches).