Cubic Zirconia Hardness: A Complete Guide

Introduction

Cubic zirconia hardness matters when you choose jewelry for daily wear. This guide explains how hard cubic zirconia really is and what that means for your jewelry collection.

Understanding hardness helps you care for your CZ jewelry properly. You’ll learn why some stones scratch others and how to keep your pieces looking new for years.

At OOTB, we’ve manufactured over 10,000 CZ jewelry styles in our 10 years of experience, and we know exactly how cubic zirconia performs in real-world conditions.

What is Hardness and the Mohs Scale?

Define Hardness

Hardness means the ability of material fights off scratches. You can imagine it like this: Dragging a key on the different surface, you will find some will be scratched, and other won’t budge. The ones that don’t scratch have higher hardness.

In jewelry, hardness tells you which stones can scratch other stones. A harder stone will always scratch a softer one, but not the other way around.

Introduce the Mohs Hardness Scale

1 to 10 is the scale of Mohs hardness. Here are items in this scale:

• 1-2: Talc powder, fingernail (2.5)
• 3: Copper penny
• 4: Iron nail
• 5-6: Glass window (5.5), steel knife (6)
• 7: Quartz crystal
• 8: Topaz
• 9: Sapphire and ruby.
• 10: Diamond

Rule: Higher numbers scratch lower numbers. A penny (3) can scratch talc (1), but glass (5.5) can scratch a penny. This can help you determine which jewelry should not be placed together. If you put a sapphire ring (9) next to a cubic zirconia ring (8.5), the sapphire may eventually scratch the CZ.

Cubic Zirconia’s Hardness Rating

Hardness of CZ

The hardness of 5A Cubic Zirconia 8.5 Mohs. This puts it in the “very hard” category, just below sapphires and rubies.
While there are different CZ grades, and the Mohs scale is different.

At OOTB, we work primarily with 4A and 5A grades to create CZ jewelry, which can offer you good quality and brilliant products.

Comparative with Other Stones

Compare to Diamond

Diamonds score a perfect 10 on the Mohs scale. The 1.5-point difference between diamond (10) and 5A cubic zirconia (8.5) means:

• A diamond can scratch CZ
• CZ cannot scratch a diamond
• Both resist scratches from most daily activities
• Both handle normal wear very well

This small difference doesn’t affect daily wear much. You won’t scratch your CZ ring by washing dishes or typing.

Compare to Other Common Gemstones

This chart shows why you should store CZ jewelry away from diamonds, sapphires, and rubies. But CZ will easily resist scratches from quartz, glass, and most everyday materials.

The Difference Between Hardness, Toughness, and Durability

Lots of people mix up these three terms. But it’s totally different. Let’s see below:

Define Toughness

Toughness measures how well a stone resists breaking or chipping when hit hard. Think about dropping your ring on a tile floor. A tough stone won’t chip or crack.

Cubic zirconia has good toughness, but not as much as diamond. A hard knock might chip CZ, even though it’s very hard to scratch.

Define Hardness (Reiterate)

Hardness only measures scratch resistance. A stone can be very hard but still break if you hit it wrong. This is the reason to understand that both hardness and toughness are important to care for your jewelry.

Define Durability

Durability combines hardness, toughness, and how well a stone handles daily wear over years. It’s the big picture of how long your jewelry will look good.

Cubic zirconia has excellent durability for most jewelry uses. The 8.5 hardness rating means it resists daily scratches well. Good toughness means it won’t chip easily. Together, these make CZ a smart choice for rings, earrings, and necklaces you wear often.

Maintaining the Sparkle of Your Cubic Zirconia

Hardness is a factor to help maintain CZ in a scratch-free state but keeping it sparkling will take more than avoiding scratches. Dirt and oils can affect even the hardest stones, causing them to appear dull.

Cleaning Tips That Work:

• Use warm water with a gentle dish soap
• Use soft toothbrush to brush your CZ jewelry lightly
• Rinse well and dry with a lint-free cloth
• For pieces you wear every day, clean them weekly.

What to Avoid:

• Do not put jewelry on before lotions or perfume.
• Avoid all harsh chemicals such as bleach or ammonia.
• Do not place your CZ jewelry in an ultrasonic cleaner.
• Do not wear CZ pieces when cleaning the house.

Have a jeweler check your settings every six months. As good as CZ is, it is still a stone that can fall out of a setting if it is not tightened appropriately. OOTB recommends this time frame based on our experience with thousands of CZ.

How to Store CZ Jewelry?

Storage is more important than you think! That 8.5 hardness rating for cubic zirconia? Anything harder than 8.5 can easily scratch your CZ pieces.

Warning Signs:

• Diamonds (10) will definitely scratch CZ.
• Sapphires and rubies (9) will scratch CZ.
• Even other pieces of CZ will scratch other CZ if they rub together.

Smart Storage Solutions:

• Use a separate soft pouch for each piece.
• Get a jewelry box with individual compartments for each piece.
• Always wrap pieces in soft cloth when traveling.
• Keep your CZ jewelry in a separate section from your diamonds or sapphires.

Why this is important: One of our customers at OOTB learned this lesson the hard way. She had stored her CZ engagement ring with her grandmother’s diamond earrings. Six months later, tiny scratches appeared on the CZ. The hardness scale doesn’t lie, harder stones will always win!

Good News? Your CZ will not scratch softer materials. You can store it with other gold, silver, or pearl jewelry without concern that your gold or pearls will be scratched.

Conclusion

With an 8.5 rating on the Mohs hardness scale, cubic zirconia is one of the harder gemstones commercially available. While not the hardness of diamonds, this hardness level provides adequate protection for daily wear.
Recall the summary:

• Hardness (8.5): Scratches from daily wear are minimized.
• Toughness—Fair, though do not subject it to hard impacts.
• Care: Clean regularly and store away from harder stones.

At OOTB, we offer high-quality CZ jewelry. If you have any business or project that needs it, contact us.

FAQs:

1. What is 6A Cubic Zirconia?

6A cubic zirconia doesn’t exist according to the current industry standards. The highest grade, and thus the highest quality, cubic zirconia is actually 5A which is rated 8.5 hardness on the Mohs hardness scale.
Some sellers have termed their cubic zirconia as “6A” and some have even termed it “7A,” but these terms do not refer to any real quality grade. The quality grading for cubic zirconia stops at 5A, because that represents the biggest quality and grade that manufacturers can consistently produce.

Related Resouces:

1. Mohs Hardness Scale – NPS