Gemstones and minerals differ in quality, as not all gemstones are capable of withstanding everyday use over a long period. Many stones can become scratched/dull after very little contact, while some rocks hold up for many years without significant wear & tear. The Mohs Hardness Scale offers insight into the differences in the properties of gemstones. With this scale in place, it provides an easy way to learn why diamonds are commonly associated with engagement rings and that other softer stones need more careful handling to maintain their original structure and beauty.

This in-depth guide will teach you what the Mohs hardness scale is, how to read a gemstone hardness chart clearly and confidently, and what it is used for.

What Is a Mohs Hardness Scale?

The Mohs hardness scale is a means of evaluating a mineral's or gemstone's ability to resist scratching. It was developed in 1812 by Friedrich Mohs, a German mineralogist, and it is unique for not using any type of artificial laboratory equipment but rather for establishing a practical system of comparison with respect to the ability to scratch another mineral.

The Mohs scale ranges from 1 to 10 (1 = softest, 10 = hardest), allowing users to quickly assess whether one mineral can scratch another. By using this method, mineral identification can be done in a fraction of the time it would take if it were being done with laboratory techniques or hardware that might otherwise be required. Consequently, the Mohs scale remains a widely accepted and utilized method for mineral identification and characterization.

What Is the Mohs Scale Used For?

A lot of people want to know what the Mohs scale is for or what the Mohs hardness scale is for. It has many useful and broad uses:

• Determining the identity of an unknown mineral
• Comparing the durability of gemstones
• Choosing durable gemstones that can be worn every day
• Understanding how resistant a piece of jewelry may be to scratches
• Choosing how best to care for and store gemstones

For many jewelers and gem buyers, the Mohs Hardness Scale is essential in helping them determine whether or not their gemstones will wear well in rings, bracelets, or other frequently worn items such as watches.

Mohs Scale of Hardness Chart for Minerals

The original Mohs hardness chart was created and developed with emphasis on minerals only and not gemstones. The standard Mineral Hardness Scale includes:

• Talc
• Gypsum
• Calcite
• Fluorite
• Apatite
• Feldspar
• Quartz
• Topaz
• Corundum
• Diamond

Each mineral can scratch and be scratched by other minerals. Therefore, for example, quartz can scratch feldspar but cannot scratch topaz.

The scale of hardness for minerals serves as the basis for determining how hard gemstones are compared to one another.

Understanding the Gemstone Hardness Scale

Application of the Mohs system on gemstones forms a Gemstone Hardness Scale (GHS), which helps consumers determine the extent to which each gemstone withstands scratch-related wear and tear as it ages.

It's important to understand that while hardness means how easily a gemstone scratches, it does not give any indication of how easily it breaks. A gemstone with a high hardness rating can still chip or shatter when subjected to force impacts. The Mohs system only indicates that it will not scratch easily.

Thus, hardness should be seen as one aspect of the overall durability of the specific type of gemstone.

Gemstone Hardness Chart

Here is a well-known chart that shows the hardness of popular gemstones and their Mohs ratings:

This information may also be presented as a gem hardness chart, a hardness of gemstones chart, or a gemstone hardness table.

Semi-Precious Stones Hardness Chart

Semi-precious stones represent a wide assortment of gemstones that are commonly found among jewel collectors today. A semi-precious stone hardness chart allows consumers to determine which type of gem needs special attention.

Some of the more common examples of semi-precious gemstones include

Many of these types of materials make excellent choices for earrings, pendants, and occasional wear items; however, their softer nature means that they may be susceptible to scratching when used in ring applications.

Hardest Mohs Scale Gemstones

Located at the top of the Mohs hardness scale are the hardest gemstones:

• Diamonds (10) - The hardest natural mineral that exists

• Corundum (9) - This category includes both rubies and sapphires.

• Moissanite (9.25) - One of the strongest types of gemstones currently utilized in jewelry design.

Due to their exceptional hardness, these types of stones make for perfect options for both engagement rings and daily-wear jewelry pieces.

Strongest Gemstones vs Hardest Gemstones

Many people confuse the strength and hardness of minerals. Hardness is simply a measure of how well something can be scratched (representing its scratch resistance). In addition to scratch resistance, strength also takes into account several additional properties:

• Hardness: The ability to resist scratching
• Toughness: The ability to resist chipping/breaking
• Stability: The ability to resist heat/light/chemical exposure

As an example, a diamond has an extremely high hardness score but may chip when subjected to impact at a sharp angle. A piece of jade is lower on the Mohs hardness scale than diamond, but is much tougher. This phenomenon is one reason gemologists will use a chart that indicates gemstone durability instead of relying simply on hardness.

Choosing the Right Gemstone for Daily Wear

When wearing a gemstone frequently (daily) as a piece of jewelry, softer stones should be avoided whenever possible and, at best, only used on special occasions and therefore protected from daily use; therefore, harder stones are typically worn daily by people who own them. Examples of harder stones include quartz, sapphires, rubies, and diamonds. Examples of softer gemstones would be opals, turquoises, and pearls.

The mineral hardness scale and the gemstone hardness system both provide you with information that extends the longevity of your gemstone-based jewelry.

Final Thoughts

The Mohs hardness scale is still used by many geologists and jewelry experts as one of the best methods for determining a mineral's hardness or the quality of gems. When researching geology or buying fine jewelry or comparing the hardness of different stones using the Mohs hardness scale chart, you can use the Mohs scale to help guide you to a suitable stone.

 The Mohs hardness chart allows you to determine which types of stones are appropriate for everyday use and which require careful handling, thus allowing you to evaluate any gem that you want according to your lifestyle and how you plan to wear it long-term.

FAQ 

What is the Mohs Hardness Scale?

This is a scale of 1-10 that measures the amount of resistance to scratching that a gemstone or mineral has.

Who created the Mohs hardness scale?

The German mineralogist Friedrich Mohs created it in 1812.

What exactly does the Mohs scale evaluate?

It evaluates scratch resistance rather than how strong a material is or how resistant it is to breaking.

Why is the Mohs scale significant to jewelers?

It helps to identify which gemstones are suitable for regular wear and which require more careful handling.

What is the hardest gemstone according to the Mohs scale?

The diamond is rated 10 on the hardness scale, making it the hardest gemstone.

Are sapphires and rubies equally capable of withstanding abuse?

Both sapphires and rubies share a rank of 9 on the Mohs hardness scale because they are classified as corundum.

Is a moissanite more robust than a sapphire?

Moissanites have a hardness rating of approximately 9.25, making them slightly better than sapphires in terms of hardness.

Does a high rating on the Mohs scale mean that a gemstone won't chip or crack?

The hardness rating only relates to the scratching ability of the stone and not its ability to chip.

Which gemstones can you wear every day?

Diamonds, sapphires, rubies, quartz, and topaz.

Which gemstones should you be careful with when using them?

The softer stones are opals, turquoises, pearls, and lapis lazuli, which require extra attention when handled.