The hardness of gemstones, an essential criterion for jewelry enthusiasts and collectors, is often assessed using the Mohs scale. This classification system, invented by Friedrich Mohs, a 19th-century German mineralogist, remains the gold standard for measuring the strength and durability of minerals. In this article, we dive into the heart of the Mohs scale, exploring how it works, its history, and its importance in choosing jewelry.
Friedrich Mohs: The Pioneer behind the Ladder
Born in 1773, Friedrich Mohs left an indelible mark in the field of mineralogy thanks to his hardness scale. As a student at the University of Halle, Germany, Mohs devised an innovative method for classifying minerals according to their relative hardness. This scale, introduced in 1812, would revolutionize the way minerals are studied and used, particularly in jewelry.
The Mohs Scale Explained
The Mohs scale ranks minerals on a scale of 1 to 10, from softest to hardest. Talc, with a score of 1, is the softest mineral, while diamond, rated 10, is recognized as the hardest. This hierarchy makes it easy to determine the ability of one mineral to scratch another.
How Does the Mohs Scale Work?
The scale is based on a simple observation: a mineral can scratch those that are softer than it. For example, corundum (sapphire and ruby), with a hardness of 9, can scratch all minerals ranked below it, but not diamond. This property is crucial for identifying minerals and choosing appropriate stones for jewelry intended for everyday use.
Beyond the Mohs Scale
Although the Mohs scale is the most famous, other systems, such as the Rockwell, Knoop, and Brinell scales, offer more precise measurements for specific applications. These complementary methods contribute to a more nuanced understanding of the hardness of materials, ranging from metals to polymers.
The Importance of the Mohs Scale in Jewelry
In jewelry, the hardness of a stone is synonymous with its longevity. Harder stones, such as diamond, sapphire, and ruby, are more resistant to scratches and impacts, making them ideal for engagement rings, wedding bands, and other daily-worn jewelry. Softer minerals, such as opal or lapis lazuli, require special attention and are often reserved for less exposed pieces.
Choosing your Jewelry according to the Mohs Scale
Knowledge of the hardness of gemstones is essential for any jewelry lover. It influences not only the choice of stones but also the care to be given to them. A diamond, through its extreme hardness, offers exceptional durability, while softer stones require delicate handling to preserve their beauty.
To better understand the resistance of the different stones used in jewelry, here is a practical table which classifies precious and semi-precious stones according to their hardness on the Mohs scale. This classification will help you appreciate the variety and beauty of stones, while taking into account their durability.
| Ladder | Precious stones |
| 2 to 3 | Amber, Pearl |
| 3 to 4 | Howlite, Coral |
| 4 to 5 | Rhodochrosite, Charoite, Kyanite |
| 5 to 6 | Apatite, Lapis Lazuli, Turquoise, Opal, Rhodonite |
| 6 to 7 | Amazonite, Marcasite, Peridot, Tanzanite, Garnet |
| 7 to 8 | Amethyst, Aventurine, Citrine, Quartz, Jasper, Tourmaline, Aquamarine, Emerald |
| 8 to 9 | Topaz, Alexandrite, Zircon |
| 9 to 10 | Ruby, Sapphire, Diamond |
At Aglaia, the choice of stones is guided by a philosophy that combines aesthetics, sustainability and ethics. We understand that each stone tells a unique story and has its own characteristics. This is why we carefully select our stones, favoring those which are not only beautiful but also capable of withstanding the tests of time.
We integrate stones of different hardness into our collections, taking into account their specific use.
Discover our semi-precious stone jewelry
The Mohs scale is not only a legacy of Friedrich Mohs, it is an indispensable tool in the field of mineralogy and jewelry. She guides professionals and enthusiasts in the choice of stones, ensuring that the jewelry not only captivates with its brilliance but also resists time. By mastering the Mohs scale, you become an informed consumer, capable of choosing jewelry intended to last a lifetime.
