Gemstone Hardness and Wearability

When choosing gemstones for jewelry, it's crucial to understand more than just how beautiful a stone looks. Gemstone hardness and wearability determine how well a gem withstands daily wear and tear.

Gemstone hardness plays a vital role in how well a gem endures regular use, but it's only one part of the wearability equation. Other factors like cleavage, tenacity, and jewelry settings also significantly influence durability.

In this article, you'll learn:

• What gemstone hardness actually means in gemology.
  
• Why even dust can damage your favorite jewelry.
  
• How tenacity, cleavage, and settings impact gemstone durability.
  
• Why some soft gemstones like opals and pearls need special care.
  
• How to choose gems suitable for everyday wear based on wearability grades.

How Hard is Dust and Why Does It Matter for Jewelry?

You might be surprised to learn that household dust can damage your jewelry. The particles floating in the air or settling on furniture contain quartz, a mineral with a Mohs scale hardness of 7 to 7.5.

Here's what makes this important:

• Quartz particles in dust are hard enough to scratch surfaces like glass, tables, or car finishes.
• The abrasiveness of dust means even routine cleaning can damage softer gemstones.
• This shows why gemstone hardness matters when selecting stones for rings or everyday jewelry.
  
  

Everyday exposure to dust highlights the importance of choosing harder gemstones to maintain polish and minimize wear.

Can a Diamond Shatter Even Though It's the Hardest Gem?

The diamond is famously known as the hardest material in the gem world, rated 10 on the Mohs scale. However, hardness does not equal indestructibility.

Here's what you need to know:

• Hardness measures scratch resistance, not toughness.
• Diamonds are indeed hard but also brittle, meaning they can shatter under impact.
• Even materials with lower hardness, like steel (5-6), can break a diamond with enough force.
  

This illustrates why even the hardest gemstones can be vulnerable to damage depending on their structure and setting.

There's an old saying among gemologists:

If you hit a diamond with a hammer, it'll shatter into a dozen pieces. Hit a piece of quartz with a hammer, it'll split in two. Hit a piece of jade with a hammer, it'll ring like a bell!

How is that possible if diamond is the hardest gem?

What Does Gemstone Hardness Really Mean in Gemology?

Hardness in gemology refers specifically to resistance to scratching, not to how easily a material breaks or chips. The term differs from its everyday meaning.

Here's how gemstone hardness works:

• Hardness is determined by the strength of atomic bonds in a gem's crystal structure.
• If one material can scratch another, it is harder at the atomic level.
• For instance, what we consider "hard" like glass, is easily scratched by many gemstones.
• Every mineral can be ranked based on what it can and cannot scratch.
  
  

Understanding this helps jewelers and buyers assess how long a gemstone can retain its shine.

What Is the Mohs Scale of Hardness and How Does It Work?

In 1812, Friedrich Mohs created a ten-point reference scale for mineral hardness. Known as the Mohs scale, it ranks materials based on their ability to scratch others.

Here's how the Mohs scale helps:

• Each mineral on the scale can scratch those below it and be scratched by those above.
• Minerals with equal hardness will not scratch each other.
• For example, ruby and sapphire can't scratch each other since they share the same hardness.
• A diamond is much harder than corundum (sapphire and ruby), even though they're only one point apart.

The Mohs scale starts approximately linear, but the curve climbs sharply at the high end. For example:

• Corundum (9) is twice as hard as topaz (8).
• Diamond (10) is four times as hard as corundum.

Only diamonds can scratch other diamonds.

How Much Can Gemstone Hardness Vary?

Gemstone hardness can vary slightly depending on the material's aggregation and chemical composition. Sometimes, what appears to be a scratch may just be residue from a softer material.

Here are key points:

• Hardness values like 5.5 are sometimes used to represent midpoints in the literature.
• Slight differences in measurement are normal and typically not significant.
• One notable exception is kyanite, whose hardness can vary greatly within a single crystal.
• Most gemstones have a very small hardness range.
  

This means wearability judgments shouldn't rely on hardness alone, especially when ranges are narrow.

What Is Tenacity in Gemstones?

Tenacity refers to a gemstone's resistance to breaking or chipping when struck. Unlike hardness, tenacity determines how a stone responds to physical impact.

For gemstones, tenacity measurements are usually given as descriptive terms:

• Very brittle
• Brittle
• Tough
• Very tough

Going back to the old saying, a diamond is both hard, defined scientifically, and brittle. The steel of a hammer (hardness 5 or 6) won't scratch a diamond, but it can shatter a diamond.

As it so happens, most gemstones would be considered "brittle." There are a few exceptions. Cryptocrystalline quartz, such as chalcedony, has "tough" tenacity. Jade, both jadeite and nephrite, has "very tough" tenacity. On the other end of the scale, zircon has a "very brittle" tenacity.

What Does Gemstone Wearability Mean?

Wearability is a broader term that encompasses hardness, tenacity, and resistance to environmental factors.

Here's how everyday actions affect gemstone wear:

• Putting hands into pockets or drawers causes gems to brush against abrasive materials.
• Soft stones will collect scratches over time, losing their polish.
• Even opal, with a hardness of 6, can become dull quickly with daily wear.
  
  

Understanding wearability helps buyers make smart decisions for long-term use.

How Does Gemstone Hardness Affect Jewelry Durability?

Gemstone hardness plays a big role in how long a gem maintains its shine. However, it must be considered in relation to environmental exposure and usage.

• Gems softer than quartz will scratch easily from dust or daily contact.
• Even wiping dust off a surface can cause damage over time.
• Stones like opal show visible signs of wear faster than harder gemstones.
• Harder gems like ruby maintain their polish much longer.
  
  

Wearability reflects more than just how a gemstone looks—it determines how it performs.

How Are Gemstone Wearability Grades Classified?

Wearability is often rated on a scale based on the stone's ability to endure regular use. This includes resistance to scratches, impacts, and chemical exposure.

Here are the grades and their meanings:

• Excellent: Safe for any setting or daily use.
• Very Good: Suitable for most types of jewelry.
• Good: Can be worn often with some caution.
• Poor: Requires special care or protective settings.
• Display Only: Should not be worn; intended for collectors.
  
  

Key takeaways:

• Pearls and opals are popular yet rated below 7 in hardness.
  
• Gems with "Poor" wearability mean its jewelry use should be very carefully considered.
  
  

Factors like gemstone cleavage also play a big role in grading.

How Does Gemstone Cleavage Influence Jewelry Durability?

Cleavage defines how a gemstone breaks when struck. It relates to how strongly the molecules of a gemstone bind to each other, much like grain in wood.

Gemstone cleavage can be categorized as:

• Perfect: Splits easily along cleavage lines.
  
• Good: Breaks with moderate force.
  
• Fair: Offers better resistance to splitting.
  
• Poor: Offers decent resistance to splitting.
• None: No cleavage planes, more durable overall.
  
  

Here's what to consider:

• Cleavage planes vary among gem types.
  
• How easily the mineral will separate along the planes affects its vulnerability.
  
  

Even diamond, with perfect cleavage, can chip or split.

How Do Jewelry Settings Impact Gemstone Protection?

Jewelry settings play a major role in preserving gemstone integrity, especially in rings which undergo the most daily stress.

Best practices for vulnerable stones:

• Avoid wearing soft stones like moonstone in rings meant for everyday use.
• Skip the Tiffany setting, which leaves the gem exposed to contact.
• Choose a protective setting, which surrounds the stone with metal.
  
  

Tips for longevity:

• Reserve soft stone rings for special occasions.
• Avoid situations where the gemstone might bump or rub against hard surfaces.
• Protective settings preserve the metal while reducing wear on the gemstone.

Why Hardness Alone Doesn't Determine Gemstone Wearability

While hardness is an essential factor, gemstone wearability is determined by several properties working together.

Here's what else plays a role:

• Tenacity determines how a stone reacts to impact.
• Cleavage affects how easily it may break or chip.
• Environmental sensitivities (heat, sweat, chemicals) also matter.
• Jewelry settings can greatly enhance or reduce wearability.
• Check our Gem Listings for detailed wearability and hardness ratings.
  
  

Choosing the right gemstone requires a balanced look at all these attributes to ensure beauty and longevity in everyday use.

Frequently Asked Questions About Gemstone Hardness and Wearability

What is the difference between gemstone hardness and wearability?

Hardness refers specifically to a gemstone's resistance to scratching, as measured on the Mohs scale. Wearability, however, is a broader term that considers several additional factors such as tenacity (resistance to impact), cleavage (likelihood of splitting), environmental sensitivities, and jewelry settings. A gem might be very hard but still unsuitable for everyday wear if it's brittle or prone to chipping.

Can soft gemstones like opals or pearls be used in rings?

Yes, but with caution. Pearls and opals are both below 7 on the Mohs scale, meaning they can be scratched by everyday dust and other materials. Their wearability grade is often "Poor," which means their jewelry use should be very carefully considered. When used in rings, it's recommended to:

• Reserve them for occasional or formal wear.
  
• Choose protective settings that shield the gem from direct impact.
  
• Avoid exposed styles like a Tiffany setting.
  

Why can diamonds shatter even though they are the hardest gemstone?

While diamond scores a perfect 10 on the Mohs scale for hardness, it also has perfect cleavage and is considered brittle. That means it can split or shatter upon a sharp blow, especially if hit along a cleavage plane. This demonstrates that hardness doesn't always equal durability.

What everyday items can scratch gemstones?

Dust particles alone can scratch gemstones that are softer than quartz (Mohs 7), since quartz is a major component of dust. Other examples include:

• Steel files (scratch feldspar and softer stones).
  
• Knives (scratch fluorite).
  
• Copper coins (scratch calcite).
  
• Fingernails (can scratch talc).
  

This is why understanding hardness is critical when choosing stones for frequently worn jewelry.

What are cleavage planes in gemstones and why do they matter?

Cleavage planes are structural features within a gemstone where atomic bonds are weaker, making it easier for the stone to split. The likelihood of breakage depends on how strongly the molecules of a gemstone bind to each other, and how easily the mineral will separate along the planes. Stones with perfect cleavage—like diamonds—are more likely to chip or break when struck.

Are there gemstones without cleavage that are more durable?

Yes. Some gemstones have poor or no cleavage, meaning they resist splitting better and can be more durable overall. For example:

• Quartz has no prominent cleavage and can withstand more physical stress than harder but more brittle stones.
  
• Cryptocrystalline quartz like chalcedony is classified as "tough" in terms of tenacity.

How should I choose a jewelry setting for softer stones?

For gems with low hardness or high cleavage, opt for settings that minimize exposure and maximize protection:

• Avoid open styles like the Tiffany setting.
  
• Use protective settings with surrounding metal.
  
• Limit use to special occasions, especially for stones like moonstone or opal.
  

The jewelry setting directly affects how long the stone will maintain its appearance and structural integrity.

Where can I find detailed gemstone hardness and wearability ratings?

You can refer to the Gem Listings on this site, which provide both Mohs hardness ratings and practical wearability grades for a wide range of gemstones. This helps buyers make informed decisions based on how they plan to wear their jewelry.

Donald Clark, CSM IMG

Donald Clark, CSM founded the International Gem Society in 1998. Donald started in the gem and jewelry industry in 1976. He received his formal gemology training from the Gemological Institute of America (GIA) and the American Society of Gemcutters (ASG). The letters “CSM” after his name stood for Certified Supreme Master Gemcutter, a designation of Wykoff’s ASG which has often been referred to as the doctorate of gem cutting. The American Society of Gemcutters only had 54 people reach this level. Along with dozens of articles for leading trade magazines, Donald authored the book “Modern Faceting, the Easy Way.”

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