Hardness scales

• Barcol hardness test
• Brinell scale
• Janka hardness test
• Knoop hardness test
• Leeb rebound hardness test
• Meyer hardness test
• Mohs scale of mineral hardness
• Pencil hardness
• Rockwell scale
• Rosiwal scale
• Scratch hardness
• Shore durometer
• Vickers hardness test
• hard water