Understanding Mohs Scale of Hardness
The Mohs Scale is a measure of the hardness of minerals. It was developed in 1812 by German mineralogist Friedrich Mohs and is currently the most widely used method of evaluating a mineral’s hardness. The scale is from 1 to 10, with 10 being the hardest, ranking minerals by their ability to scratch or be scratched by other minerals.
Breakdown of the Mohs scale:
• 1: Talc – It is the softest mineral on the scale and can be scratched easily with a fingernail. (Not used as a gemstone)
• 2: Gypsum – It is slightly harder that talc, but it is still relatively soft and can be scratched with a fingernail. (Not used as a gemstone)
• 3: Calcite – It is harder that talc and gypsum and cannot be scratched with a fingernail but can be scratched by a copper penny or a knife blade. (Not commonly used in jewelry due to its softness)
• 4: Fluorite – It is harder that calcite and can scratch steel knives, but it is still relatively soft. (Not commonly used in jewelry due to its softness)
• 5: Apatite – It is slightly harder that fluorite and can scratch glass. (Not commonly used in jewelry due to its softness)
• 6: Feldspar – It is harder than apatite and can scratch glass easily. (Not commonly used in jewelry)
• 7: Quartz – It is one of the hardest minerals and can scratch window glass. (Commonly used in jewelry, including varieties such as Amethyst, Citrine, and Smoky Quartz)
• 8: Topaz – It is harder that quartz and can scratch glass with ease. (Commonly used in jewelry, including varieties such as Blue Topaz and Pink Topaz)
• 9: Corundum – It is one of the hardest minerals and can scratch most other minerals. (Commonly used in jewelry, including varieties such as Sapphire and Ruby)
• 10: Diamond – It is the hardest mineral and can scratch all other minerals. (Commonly used in jewelry for engagement rings and other pieces because of its durability)
Gemstones that fall lower on the Mohs scale, such as calcite, fluorite, and apatite, are not commonly used in jewelry due to their softness and low durability. Gemstones that fall higher on the Mohs scale, such as Corundum and Diamond, are highly prized for their hardness and durability.
