what is the hardness number of aluminium.....? what is the hardness number of aluminium-Sic composite material...?I don\'t believe that Aluminum (US spelling)/ Aluminium (UK spelling) has a Mohs Hardness rating. The Hardness of a material, as measured by the Mohs Hardness scale, is a criterion of its resistance to crushing. [Perry\'s Chemical Engineering Handbook]. Since aluminum is a metal, and would deform under a crushing-type stress, rather than shatter, it would not have a Mohs Hardness rating. Perhaps you meant **aluminA**, rather than aluminum. Alumina (Al2O3) has a Modified Mohs Hardness of 12. Silicon Carbide (carborundum) has a Modified Mohs Hardness of 13. There\'s no value listed for the combination, but it should be pretty hard stuff -- likely in the 12-13 range, but potentially even harder. Hope that helps.Other related question