Lab grown diamond, moissanite or cubic zirconia?

Side by side

What is each stone?

Lab grown diamond. It is the same carbon crystal as a mined diamond, with the same hardness, fire and sparkle. The only difference is where it comes from. US FTC rules say it must be labeled as lab grown.

Moissanite. Silicon carbide, made in a lab to look like a diamond. Moissanite found in nature is extremely rare, so all moissanite used in jewelry is made in a lab.

Cubic zirconia. Zirconium dioxide. It has been sold as a gem since the 1970s, and it is the most common diamond imitation.

"Lab grown" tells you where a stone was made, not what it is. That is why people mix up moissanite and lab grown diamonds. Only one of them is a diamond.

Which is best for daily wear?

The Mohs scale ranks how well a stone resists scratches. Diamond is 10, the top of the scale. Moissanite is 9.25 and CZ is 8 to 8.5.

The steps on the scale are not equal. The jump from 9 to 10 is huge, so a diamond is much harder than the numbers make it look. Of the three, a diamond is the stone made for a lifetime of daily wear. CZ is better for jewelry you wear now and then.

Which one sparkles more?

A diamond shows white sparkle, called brilliance, mixed with flashes of color. This is the look people know as "a diamond".

Moissanite throws strong rainbow flashes, more than twice the color of a diamond. Some people like that. Many people feel it looks less like a diamond, and at 1 carat and up the rainbow often shows that the stone is not a diamond. When a jeweler looks with a loupe, moissanite also shows doubled facet edges. A diamond never does.

CZ sparkles less than a diamond and gets duller as it wears.

How does each look after 10 years?

A lab grown diamond looks like the first day once it is cleaned. Only another diamond can scratch it. Lotion and skin oil make any stone look dull until you clean it.

Moissanite stays bright. It is hard and rarely scratches.

CZ shows its age first. Fine scratches and worn edges make it look dull, and it can turn slightly yellow.

What about price?

CZ costs a few dollars. Moissanite costs much less than a lab grown diamond, because it is a different and cheaper material. It is not a diamond. A lab grown diamond costs more than both, and much less than a mined diamond of the same size and quality. What you pay for is a diamond.

Which stones come with a grading report?

Lab grown diamonds do, from labs like IGI or GIA. An IGI report lists the carat, color and clarity, plus a cut grade on round stones. It also confirms the stone is a diamond. Since October 2025, GIA rates lab grown diamonds as Premium or Standard instead of giving color and clarity grades. Moissanite never gets a diamond report, and CZ comes with no report.

Can a diamond tester tell them apart?

• Heat testers read diamond and moissanite the same way, so moissanite can pass as "diamond". CZ fails.
• Electrical testers catch most moissanite, because it conducts electricity and diamond usually does not.
• A few lab grown diamonds have a trace of boron and can read as "moissanite" on an electrical tester, even though they are diamond. The grading report settles it.

How to choose

• Lab grown diamond if you want a diamond. It is the hardest stone, it has a bright white sparkle, and it comes with a grading report. It is the only stone we use.
• Moissanite if budget comes first and you love rainbow sparkle. It holds up well, but it is not a diamond.
• CZ for fashion jewelry, travel or a placeholder ring. It is not made for years of daily wear.

At Next Diamonds

We only sell lab grown diamonds. My brother and I have worked in fine jewelry since 2009, and we chose to work only with lab grown diamonds. Every center stone comes with a grading report. Read what a lab grown diamond is or see all engagement rings.

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