All four sparkle. "Crystal" on its own usually means glass, the softest of the group. A lab-grown diamond is diamond, a 10 on the Mohs hardness scale, grown instead of mined. Moissanite rates 9.25, with extra rainbow fire. And cubic zirconia, a durable 8.5, gives you a diamond's bright, white look at an accessible price, which is why it's the go-to for detailed, many-stone designs.
Most comparisons online come from people selling one of these, and it shows. Our cards, face up: we sell two of them. Our everyday pieces are set with cubic zirconia, on purpose, and Oomiay Fine uses lab-grown diamonds. Here's the plain comparison, then why we use each.
The quick comparison
On the Mohs scale, a higher number means harder to scratch. Fire is the flash of rainbow color a stone throws as it moves.
| Material | What it is | Mohs hardness | Sparkle | Price | Best for |
|---|---|---|---|---|---|
| Glass crystal | Manufactured glass, made in almost any color | 4 to 7, depending on the glass | A softer shine than gems | Lowest | Color, milky and opal-like effects |
| Cubic zirconia | Lab-made zirconium oxide, in jewelry since the late 1970s | 8.5 | Bright, with slightly more fire than diamond | Accessible | Pavé, tennis lines, mixed cuts, color |
| Moissanite | Lab-made silicon carbide | 9.25 | More than twice the fire of diamond | Mid | A large center stone that takes daily knocks |
| Lab-grown diamond | Diamond grown in a lab | 10 | Diamond brilliance | Mid to high | Pieces where the word "diamond" matters to you |
| Mined diamond | Natural diamond from the ground | 10 | Diamond brilliance | Highest | Fine jewelry and heirlooms |
Sources: GIA on simulants, gem imitations and diamond alternatives; Geology.com for glass.
Let the sparkle be the affordable part.
Is cubic zirconia real?
It's a lab-made material with a name of its own, neither a natural gem nor a diamond. Cubic zirconia is made by heating powdered zirconium oxide to its melting point, a method that reached jewelry in the late 1970s (GIA). Gemologists file it under simulants, meaning it looks like another gem while having its own chemistry and properties (GIA).
Any fakery would live in the label. CZ sold as diamond is a con. CZ sold as CZ, at a CZ price, is simply jewelry.
Cubic zirconia vs crystal: what's the difference?
Hardness and color. On a product page, "crystal" by itself usually means glass: the Corning Museum of Glass defines the word as a popular name for brilliant, colorless lead glass. Glass sits at about 4 to 7 on the Mohs scale, so it picks up scuffs sooner than CZ. Glass wins on color: it can be made in virtually any shade, even an opal look (GIA).
We use both, each where it's strongest. Cubic zirconia, graded 5A, does most of the sparkling in our collection. Where a color calls for it, we switch to Exclusive Oomiay glass crystals, for their shades and soft, milky effects. Mystic topaz is our color-shifting crystal, not mined topaz (here's how the effect works).
Charmed mixes them on one Black Gold band: round mystic topaz crystals alternating with small lilac moonstone crystals, $69.
“This ring is another stunner. Even in its understated simplicity, it still catches the light and the eye. I can't stop looking at it. It is just lovely.”
Cubic zirconia vs moissanite: which is better?
For one large stone you'll knock against everything for years, moissanite. For almost everything else, cubic zirconia.
Moissanite has real strengths. GIA puts it at 9.25 with "excellent toughness," and it throws more than twice the fire of diamond (GIA). It has trade-offs too: in large sizes, GIA says, all that fire can make it look "artificial," and some stones carry a slight greenish or greyish tint.
CZ is far more accessible, and that adds up fast. One costly stone fits in a ring's budget. Dozens of them in a pavé band, or a hundred in a tennis necklace, decide the design for you.
What does 5A cubic zirconia mean?
5A, also written AAAAA, is the top grade on the letter scale the cubic zirconia trade uses for its stones. Makers grade their own stones on it. No gem lab issues the grade, and no standards body publishes what each letter requires, so read it as the maker's quality call rather than a certificate.
Sellers, us included, reserve it for their best-cut, clearest stones. The rest you can check yourself: stones that sit level, facets that light up evenly and metal holding each stone (here's what to look for up close).
Does cubic zirconia get cloudy?
Mostly, it gets dirty. Skin oil, lotion and soap leave a film, and the back of a stone collects a lot of oil and dirt, GIA notes. That film blocks light, and a soft, dry cloth usually clears it.
One moissanite maker tells readers CZ "typically lasts only 2-3 years with regular wear" and that its cloudy look "can't be fixed through cleaning." Here's the fair version. Scratches don't wash off, and CZ scratches more easily than diamond (GIA), so years of knocks can wear facet edges and dull a stone. Like most stones, it can also chip if it meets a countertop hard; GIA points out that even diamond can fracture from a hard blow. But CZ outranks quartz and steel on the hardness scale (Geology.com), so it handles daily wear well. A stone that looks foggy after a year usually needs a wipe, not replacing.
To keep it bright:
- Give it a once-over with a soft cloth when you take it off.
- Skip the cleaners. Plated pieces do best with a soft, dry cloth: no cleaning agents and no ultrasonic machines.
- Store pieces apart, so harder pieces can't scratch softer ones (GIA).
- Let creams sink in first. Jewelry goes on once your skin products have soaked in, and comes off for the gym, housework and bed. Our care guide has the rest.
Why our everyday pieces use cubic zirconia
We'd rather spend on the parts you can see. Cubic zirconia keeps the stone affordable, so the budget goes into the design, the setting and the finish around it.
Stiletto, $69, is an open gold band that ends in a polished teardrop on one side and a dome of pavé crystals on the other. The Silver Mixed Shape Tennis Necklace, $169, is hand-linked, and its cut keeps changing along the line: rounds, ovals, pears and emerald cuts, each in its own prongs. In mined diamonds, a line of stones this size would run well over $10,000. Ours is $169, so you're paying for the design, not the carat count.
Each crystal goes in by hand, nearly every ring design runs from size 4 through 11, and each piece is covered by a two-year warranty.
Know what you're wearing
A diamond is the right buy when the diamond is the whole point, and that's what Oomiay Fine is for. For the rest of your jewelry box, let the sparkle be the affordable part.
See 5A cubic zirconia, set by hand.
Shop the story
Stiletto Ring
Silver Mixed Shape Tennis Necklace
Charmed RingQuestions about cubic zirconia
Is cubic zirconia real?
Cubic zirconia is a lab-made material (zirconium oxide), not a natural gem or a diamond. Gemologists call it a simulant: it can look like another gem but has its own chemistry and properties.
Which is better, cubic zirconia or moissanite?
Moissanite is harder (9.25 against 8.5 on the Mohs scale) and has more fire. Cubic zirconia costs far less, which makes it the practical choice for pavé, tennis pieces and designs with many small stones.
What does 5A cubic zirconia mean?
5A is the top grade on the letter scale the cubic zirconia trade uses for its own stones. It's set by the maker, not by a gem lab, and no standards body defines it.
Does cubic zirconia get cloudy?
A cloudy look is usually a film of skin oil, lotion or soap, which a soft, dry cloth usually clears. Over years, scratches on the facets can dull a stone, and those don't wash off.
Is cubic zirconia worth it?
For jewelry you want to wear often and enjoy without a diamond price, yes. It's hard enough for daily wear, and the money you save can go into the design and how the stones are set.
Is moissanite a lab-grown diamond?
No. Moissanite is silicon carbide, a different material from diamond, with its own hardness (9.25) and much stronger fire. A lab-grown diamond is diamond, with the same properties as a mined one.
Wink Ring
Spell Ring
Gold Double Hoop Dangle Earrings
Gold Star Bezel Tennis Necklace