When shopping for gemstones or jewelry made with gemstones, you may come across statements like “Mohs Hardness 3-5” but what does this all mean? Today, I am happy to share with you a quick guide to understanding gemstone hardness.
A gemstone’s hardness also know as the stone’s scratch resistance, is measured using something called the Mohs Scale of Relative Mineral Hardness. It is a scale that has been in use since 1812 and was designed to test the ability of a harder material to scratch a softer material. If a mineral scratches another, they belong to the same hardness level/scale.
1 – 2 Soft: Can be scratched with a fingernail
3 – 5 Medium Soft: Can be scratched with a steel knife
6 – 7 Medium Hard: Can be scratched with a window glass
8 – 10 Hard: Can be scratched with a diamond
Some sample gemstones in each of these categories are:
Hardness Group: Soft
Autumn Hickoryite – Hardness Group: Medium Soft
Amazonite – Hardness Group: Medium Hard
Ruby – Hardness Group: Hard