Hardness is a measure of how hard a material is. Hard things resist pressure. Some examples of hard materials are diamond, carbides, quartz, tempered steel, ice, granite, concrete. Ability of material to resist wear, tear, scratching, abrasion cutting is called hardness. Ex, Dimond and Glass are harder material.
Harder materials are more difficult to cut and shape than softer ones. They are also usually more brittle which means they do not bend much but can shatter. Hard materials are important in industry. Cutting tools, machines and construction materials are usually hard.