12 Carat Topaz (Oval, 18.3×12.2mm, Blue)

Color:

blue

actual size

Actual size is set for screen

How big is a 12 carat oval-cut Topaz?

It depends on the cut parameters and length-to-width ratio, but a typical size of a 12ct oval-cut Topaz would be around 18.3×12.2 mm (±6%). The lw ratio of this Topaz is 1.5. See below how big it looks on a ring and finger.

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	73 %

Saved...

Ring diameter: 16.9 mm

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Additional Info

Topaz is a gemstone of many colors. It’s commonly found colorless (white) and then treated to achieve desired colors. Blue Topaz is the most common and popular color variety.

Where to buy?

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

Gem Details

Name:	Topaz
Shape:	Oval
Chemical Formula:	Al₂SiO₄(F,OH)₂
Crystal Structure:	Orthorhombic
Hardness:	8
Specific Gravity	3.53
Carat weight:	12 ct
Gram weight:	2.4 g (0.0847 ounces)
Points:	1200 pts
Length:	18.3 mm
Width:	12.2 mm
Est. face-up size:	183.07 mm²
Volume:	679.89 mm³
Length-to-width ratio:	1.5
Refractive Index:	1.610 - 1.638
Luster:	Vitreous
Wearability:	Very good
Care Instructions:	Avoid hard hits or drops
Color:	Topaz can be found in the following colors:
Birthstone:	Topaz is a birthstone for the month of December

Popular comparisons:

About Topaz Specific Gravity

Topaz has a specific gravity of approximately 3.49 - 3.57, with 3.53 being a generally accepted standard average for gem-quality material.

For all the Topaz size calculations on this website, the specific gravity of 3.53 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: 12ct Topaz vs Quartz (Oval Cut)

If you want to compare oval-cut Topaz sizes from 0.25 to 40ct on one page, see Oval Cut Topaz 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).