On the Mohs scale of mineral hardness, which ranges from 1 (softest) to 10 (hardest), onyx has a hardness level of about 6.5 to 7. This places it in the category of moderately hard minerals. It is softer than some other popular gemstones like diamonds, sapphires, and rubies, which are rated 9 and higher, but it is harder than many common materials, making it suitable for use in various types of jewelry and decorative objects. Onyx’s hardness allows it to be polished and carved into intricate designs, and it can withstand everyday wear in jewelry items like rings, earrings, and pendants, although care should be taken to prevent scratches and damage.