3 Carat Spinel (Round, 8.93mm, Red)

Color:

red

actual size

Actual size is set for screen

How big is a 3 carat round-cut Spinel?

It depends on the cut proportions, but typically a 3ct round-cut Spinel would measure around 8.93 mm (±4%) in diameter. You can check the finger coverage in the simulator below.

Ring:

Gold
Platinum

Skin tone:

Pale
Light
Medium
Dark

Ring width: 3.0 mm

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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	53 %

Saved...

Ring diameter: 16.9 mm

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Additional Info

Spinel is a rare gemstone that occurs in practically all colors. Because of similar properties, red and blue Spinels have often been mistaken for Rubies and Sapphires. For example, the Black Prince's Ruby is actually a Spinel.

Where to buy?

For certified gemstones, high-end gemstone jewelry, and birthstone jewelry, see Blue Nile

Gem Details

Name:	Spinel
Shape:	Round
Chemical Formula:	MgAl₂O₄
Crystal Structure:	Isometric
Hardness:	7.5-8
Specific Gravity	3.6
Carat weight:	3 ct
Gram weight:	0.6 g (0.0212 ounces)
Points:	300 pts
Length:	8.93 mm
Width:	8.93 mm
Average diameter:	8.93 mm
Est. face-up size:	62.63 mm²
Volume:	166.67 mm³
Length-to-width ratio:	1
Refractive Index:	1.712 - 1.736
Luster:	Vitreous
Wearability:	Excellent
Care Instructions:	No special or unusual care
Color:	Spinel can be found in the following colors:
Birthstone:	Spinel is not an official birthstone of any month

Popular comparisons:

About Spinel Specific Gravity

Spinel has a specific gravity of approximately 3.58 - 3.62, with 3.6 being a generally accepted standard average for gem-quality material.

For all the Spinel size calculations on this website, the specific gravity of 3.6 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: 3ct Spinel vs Alexandrite

If you want to compare round-cut Spinel sizes from 0.25 to 40ct on one page, see Spinel 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).