The Mohs Scale of Hardness

Posted on May 25th, 2023 05:50 PM

The Mohs hardness scale consists of a series of ten standard minerals used to assess the relative hardness of minerals and other objects. Mohs hardness is a measure of a material's resistance to abrasion or scratching. It is worth noting that a gem or mineral that is hard may not necessarily be tough or durable. The mineral hardness scale is an ordered scale that evaluates the hardness of minerals based on their ability to scratch softer materials.

Naturally, variations in hardness can exist among different materials due to their composition or impurities, resulting in some falling within intermediate ranges. Each of the ten minerals and gems on the scale will scratch those with a lower number while being scratched by those with a higher number. It is important to understand that the hardness scale is not linear, meaning that a higher value does not indicate a fixed percentage increase in hardness compared to the preceding value.

Who Discovered It? 

Friedrich Mohs, a German mineralogist, is credited with the discovery of the Mohs hardness scale in 1812. He created this scale as a method to assess the comparative hardness of minerals and other substances. By conducting extensive tests and careful observations, Mohs handpicked ten minerals with different levels of hardness and arranged them in a specific order based on their scratching abilities. This groundbreaking work by Friedrich Mohs has had a long-lasting influence on the field of mineralogy, establishing the Mohs hardness scale as a fundamental tool for identifying and characterizing minerals.

Why is hardness important?

Excellent hardness has major implications in a variety of industries. Many different materials may be formed or polished using abrasives. The Mohs hardness scale is vital to many disciplines, but it is especially important to the fields of geology, mining, and materials research. The following are some justifications for the significance of the Mohs hardness scale:

Understanding the hardness of different materials helps in choosing appropriate substances that can withstand wear, abrasion, or impact. The scale provides a practical and standardized method for identifying and distinguishing minerals based on their hardness characteristics.

The Mohs hardness scale assists in evaluating and grading gemstones. Gems with a higher hardness are less prone to scratching or damage, making them more desirable and valuable for use in jewelry. The scale allows for a comparative analysis of the hardness of different minerals and materials. It provides a standardized reference point for scientists and researchers to compare the physical properties and characteristics of various substances.

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Testing a Stone's Hardness on The Mohs Scale:

Moonstone's Healing Properties

The Mohs scale makes it simple to determine a stone's hardness. A step-by-step guide is provided below!

To test a stone's hardness using the Mohs Scale, you will need a set of reference minerals such as talc, gypsum, calcite, fluorite, apatite, orthoclase feldspar, quartz, topaz, corundum, and diamond. These minerals can be obtained as small samples or in mineral testing kits.

Commence the test by using the softest reference mineral, talc (level 1), to attempt to scratch the stone's surface.

Continue the process, testing each mineral on the scale on the stone's surface until you find the one that scratches it.

Once you discover the reference mineral that successfully scratches the stone, take note of its corresponding level on the Mohs Scale, which indicates the stone's hardness level.

For accurate results, conduct the scratch test on various areas of the stone's surface. Consistent outcomes will allow you to confidently determine the stone's hardness level.

Using the Mohs Scale to test a stone's hardness can aid in identifying the stone, assessing its durability, and comprehending its potential applications across different industries.

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Different Levels of Hardness on the Mohs Scale:


The Mohs scale of hardness classifies the toughness of common minerals within a spectrum spanning from 1 to 10. Ascending numbers correspond to augmented hardness, where 10 denotes the pinnacle of resilience and 1 signifies the nadir of softness. Amongst gemstones, diamonds reign supreme as the epitome of unyielding solidity, trailed closely by the illustrious corundum family encompassing Yellow Sapphire and Rubies, which rank just below diamonds in their indomitable nature. In stark contrast, talc, residing at the polar end of the scale, emerges as the paragon of gentleness, occupying the esteemed position of no. 1. If a mineral's hardness straddles the boundary between two integers, it finds itself embraced by the encompassing aura of 5. So, let's explore the varying hardness levels of different gemstones! 


Ultimately, the Mohs Scale of Mineral Hardness stands as a vital instrument engaged in the realms of geology, mineralogy, and materials science, enabling the assessment and comparison of diverse minerals' hardness. Spanning a spectrum of 10 levels, commencing from the gentle touch of talc and culminating in the unyielding brilliance of the diamond, this scale establishes an established benchmark, fostering comprehension of the relative hardness exhibited by an array of substances.

Furthermore, the Mohs Scale plays a significant role in the appraisal and classification of precious gemstones. In its entirety, this scale crafts a standardized framework, beckoning scientists, researchers, and enthusiasts alike to delve into the exploration and juxtaposition of minerals and materials' physical attributes.

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