Carat Difference in Size in Cubic Zirconia

by Shanna

I keep buying cubic zirconia rings, and when they arrive they look huge! I would like a 1 - 2 carat ring, but what is the carat difference so I can make better buys. Thanks!

Hi Shanna,

The carat of any type of gemstone, including man-made gemstones like cubic zirconia, is a measurement of the weight of the stone – not the size of the stone. A 1 carat stone will weigh 0.2 grams, or 200 milligrams, and the 1 carat size for each gemstone will depend on the density of the stone.

Find Our Top Cubic Zirconia Ring Picks On This Page!

Diamonds have a density of 3.5 – 3.53 while the heavier cubic zirconia gemstones have a density of 5.5 – 5.9. Because of the difference in densities, a 1 carat cubic zirconia gemstone will actually be slightly smaller than a 1 carat diamond.

A 1 carat stone will look larger or smaller to the eyes too, depending on how the gemstone is cut. For example, an emerald cut stone carries most of the weight on top and an Asscher cut carries most of the weight under the top of the stone. So, a 1 carat Asscher cut gemstone will look smaller than a 1 carat emerald cut gemstone.

Also, cubic zirconia tends to look larger than a diamond even for comparably sized stones because cubic zirconia has a higher rate of light dispersion than a diamond - which means cz sparkles more than a diamond. This sparkly effect makes cz stones look larger to the eye than they really are. You can find out more about how Cubic Zirconia Compares to a Diamond on this page.

Cubic zirconia tends to look more like a diamond in sizes ranging from 0.30 to around 1.5 carats in size. Once you start reaching sizes of around 2 carats, a cubic zirconia looks a lot less like a diamond because of its dazzling light reflective qualities. But the 3/4 (three-quarter) cubic zirconia gemstone size is really the most ideal carat for the most realistic diamond-looking ring.

How can you order a cubic zirconia ring that is not too big? With a ruler! (And also keep the ideal 3/4 carat size for cubic simulants in mind).

Look closely at the description of the cubic zirconia ring, and you should see the width of the center stone in millimeters. If you have a 1 inch ruler or measuring tape, flip it over to the centimeter side – 10 millimeters equal 1 centimeter. Most rulers or measuring tapes will show 1 millimeter notches between the centimeter measurements.

You can mark the measurements of the cubic zirconia stone out on a piece of paper to gain a visual impression of how large the stone will look.

In terms of millimeter size, look for cubic zirconia stones that are about 5mm or smaller in width, once you start reaching around 7mm is when you get into the "fake" looking territory.

I hope this info helps, and do write back if you have any additional questions!

Suzanne Gardner
Everything Wedding Rings

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CZs are unique and beautiful and not just fake diamonds!
by: Anonymous

A useful article, but I have to disagree with your statement that CZs look 'fake' if they're too large. Personally, i think they look wonderful and unlike any other stone - man-made or natural - and their affordability is just a bonus!


Like many things - the look of CZs are highly subjective depending on the viewer! In my personal experience, for those looking for more dimaond-like rings the smaller CZs look more realistic than the larger ones particularly because of the size issue - but for those who love plenty of bling, the larger CZs will definitely offer a ton of sparkle and shine!

Suzanne - Everything Wedding Rings

Very useful information
by: Jean

Thank you so much for the very helpful information on choosing the size of cz stones. Your recommendations fit my experience in buying stud earrings. It is especially helpful to now be able to make online choices by keeping in mind the 5 mm limit.

- Your welcome Jean, I'm so glad that this article was helpful in your CZ shopping!
Suzanne Gardner, Everything Wedding Rings

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