Moissanite vs. Cubic Zirconia (CZ): Why Is Moissanite 20x More Expensive? A Side-by-Side Comparison of Sparkle, Durability, and Value.

Moissanite and cubic zirconia (CZ) are both lab-made diamond alternatives. They look similar from a distance, but they behave very differently in light and in daily wear. That is why a 6.5 mm moissanite can cost 20 times more than a similar-size CZ. Below is a side-by-side look at sparkle, durability, and long-term value, with the “why” behind each difference.

What They Are (and Why That Matters)

Moissanite is lab-grown silicon carbide (SiC). The mineral was first found in a meteor crater, which is why it’s rare in nature. Growing SiC as clear gemstones is hard: crystals form slowly, at very high temperatures, with a lot of quality control to avoid color tints.

Cubic zirconia is lab-grown zirconium dioxide (ZrO2) stabilized with small amounts of other oxides. It’s easy to produce in large, flawless boules. That’s why CZ is cheap and plentiful.

Both are ethical and lab-made. The key differences come from physics: how each material bends light and resists wear.

Sparkle: Brilliance, Fire, and the Overall Look

Brilliance is the white light returned to your eye. The higher the refractive index, the more light stays in the stone and bounces back.

• Moissanite RI: about 2.65–2.69 (very high). This gives strong brightness.
• CZ RI: about 2.15–2.18. Bright, but lower than moissanite.

Fire is the rainbow flash (dispersion). The bigger the number, the more color you see.

• Moissanite dispersion: about 0.104 (very fiery—more than diamond).
• CZ dispersion: about 0.06 (fiery, but clearly less than moissanite).

Why this matters: Moissanite returns more white light and more colored light. In sunlight, moissanite throws dramatic rainbow flashes. Indoors, it still looks bright. CZ sparkles, but with less intensity. Freshly cut CZ can look flashy in store lighting, yet it tends to lose crispness with wear (more on that below).

Character of the sparkle: Moissanite is doubly refractive (birefringent). Light splits inside the crystal, which can make facet lines appear doubled if you look closely through a loupe. This contributes to a lively, sometimes “too much fire” look in sizes above ~2 carats for those who prefer a calmer style. CZ is isotropic (single refractive), so it shows a simpler pattern of flashes. Some people prefer that quieter look.

Durability and Daily Wear

Durability is where the price gap really shows up in daily life.

• Hardness (scratch resistance): Moissanite ~9.25–9.5 on Mohs; CZ ~8–8.5. The higher the number, the less everyday grit will scratch it. In a year of daily wear, moissanite usually keeps its sharp facet edges. CZ often develops tiny scratches and rounded facets that dull its sparkle.
• Toughness (resistance to chipping): Moissanite is tough with no cleavage. CZ has no cleavage either, but it’s more brittle. Facet edges on CZ can chip, especially in rings.
• Heat and bench work: Moissanite handles heat well. Jewelers can usually resize or repair rings without removing the stone. CZ is more sensitive to thermal shock and may crack with rapid heating or cooling. Many jewelers remove CZ before torch work.

Why this matters: Hardness and toughness control how a stone looks after months and years. Moissanite’s polish and facet definition hold up, so it stays bright. CZ tends to haze from micro-scratches and loses the crisp “brand new” look. That drives long-term value.

Color and Clarity

• Moissanite: Available in near-colorless to colorless ranges. High-end stones are graded to reduce warm or greenish undertones. Achieving that requires tight growth control and more rejection of off-color boules, which raises cost.
• CZ: Usually looks “D-flawless” right out of the box—perfectly colorless and very clean—because it’s easy to grow in large, uniform crystals. However, the appearance can turn slightly “milky” over time as fine scratches and residue scatter light.

Why this matters: If you’re picky about color in bright daylight (where warmth is easier to spot), choose a colorless-grade moissanite. For one-time events or occasional wear, CZ’s crisp, initial whiteness is appealing and inexpensive.

Size and Weight: How Big Will It Look?

• Specific gravity (density): Moissanite ~3.2; CZ ~5.8.
• For the same millimeter size (say 6.5 mm, a “1 ct diamond look”), CZ weighs much more than diamond, and moissanite weighs a bit less. That affects carat-equivalent labels and how settings feel.

Why this matters: If you shop by millimeter size (how big it looks), a 6.5 mm moissanite will be bright and light on the finger. A 6.5 mm CZ looks the same size but is heavier. Carat numbers can be confusing across materials, so always check the millimeter measurement.

Why Is Moissanite 20x More Expensive?

The price gap is mostly about manufacturing difficulty, cutting costs, and supply.

• Crystal growth is harder: High-quality moissanite is grown at very high temperatures (well over 2000°C) with slow growth rates and careful control to prevent unwanted color and defects. Yields are modest, and a lot of material gets rejected. CZ can be grown quickly, in large boules, with high yields.
• Cutting and polishing are costlier: Moissanite’s high hardness wears out diamond tools faster and takes longer to polish to a crisp finish. CZ cuts and polishes quickly at much lower cost.
• Orientation and selection: To minimize optical doubling and optimize sparkle, moissanite often needs specific cutting orientations, which can reduce yield from each crystal. CZ has fewer constraints.
• Quality control and grading: Moissanite suppliers spend more on color and clarity sorting, and many offer lifetime brilliance guarantees. CZ is a commodity with minimal grading overhead.
• Market structure: There are relatively few high-grade moissanite growers compared to many CZ producers. Limited supply and brand support keep prices higher.

Typical retail comparison for a 6.5 mm (1 ct diamond-size) round:

• Moissanite: roughly $250–$700, depending on brand, color grade, and cut quality.
• CZ: roughly $5–$30 for the loose stone; often under $100 even when set.

Those ranges vary by seller, but a 20x (or more) difference is common. The gap reflects the time, energy, tooling, and rejection rates baked into moissanite.

Value Over Time

Appearance over years: Moissanite keeps its polish and sparkle with normal care. CZ tends to show wear faster. That means CZ can look “tired” next to a well-kept moissanite after steady use.

Resale: Neither is a “store of value” like gold. But moissanite can have some secondhand value. CZ generally has none.

Cost of ownership example:

• If a CZ center stone in a ring gets replaced every 2–3 years due to dulling or chipping, you may pay for the stone plus bench labor repeatedly. Over 8–10 years, that can exceed the price of a single moissanite.
• Moissanite usually requires one purchase and routine cleaning, with no stone replacements.

Why this matters: For daily-wear jewelry, moissanite’s higher upfront cost often pays off in fewer replacements and a better long-term look.

Heat, Chemicals, and Care

• Heat: Moissanite tolerates bench heat well. CZ is vulnerable to thermal shock; quick temperature swings may crack it.
• Chemicals: Both handle normal household chemicals, but avoid harsh abrasives. CZ scratches more easily, so be gentle.
• Cleaning: Warm water, mild dish soap, and a soft brush work for both. Ultrasonic and steam cleaning are safe for moissanite; for CZ, ask your jeweler—micro-fractures or loose settings can worsen with aggressive cleaning.

Testing and Identification

• Diamond testers: Thermal diamond testers will often flag moissanite as “diamond” because moissanite conducts heat well. Combination testers (thermal + electrical) can separate them. CZ usually reads as “not diamond.”
• Loupe check: Look for doubled facet edges in moissanite; CZ shows single lines.
• Weight: CZ is much heavier than moissanite for the same size. Jewelers can spot this quickly.

When to Choose Which

• Choose moissanite if: You want an engagement ring or daily-wear piece that stays bright for years, you care about top-tier sparkle, and you don’t want to replace stones often.
• Choose CZ if: You need a very low-cost, large-look fashion piece, a travel stand-in you won’t worry about, or earrings/pendants that won’t see hard wear.

Practical buying tips:

• For moissanite, prioritize cut quality and a color grade you like in daylight. If big stones feel “too rainbow,” consider slightly smaller sizes or warmer lighting.
• For CZ, buy from a reputable source with good polish quality. Consider protective coatings if offered, and plan for gentler wear or periodic replacement.
• Always size by millimeters, not “carat equivalent,” to avoid confusion.

Quick Specs at a Glance

• Material: Moissanite = silicon carbide; CZ = zirconium dioxide.
• Refractive index (brilliance): Moissanite ~2.65–2.69; CZ ~2.15–2.18.
• Dispersion (fire): Moissanite ~0.104; CZ ~0.06.
• Optic character: Moissanite = double refraction; CZ = single refraction.
• Hardness (Mohs): Moissanite ~9.25–9.5; CZ ~8–8.5.
• Toughness: Moissanite = excellent; CZ = fair (more brittle).
• Specific gravity: Moissanite ~3.2; CZ ~5.8.
• Heat tolerance: Moissanite = high; CZ = sensitive to thermal shock.
• Typical price (6.5 mm round): Moissanite ~$250–$700; CZ ~$5–$30 (stone only).

Bottom line: Moissanite costs far more because it’s harder to grow, tougher to cut, and built to hold its sparkle under real daily wear. CZ is a great budget look for occasional use and big fashion pieces. If your ring is something you’ll wear every day for years, moissanite’s brightness, durability, and lower long-term maintenance are why many people consider it worth the premium.