Although diamond is the hardest mineral in nature, it can also be damaged. Explain from hardness and firmness. Hardness: refers to the frictional resistance of substances; Hardness: the ability of a substance to resist cracking and chipping. Although diamond is the hardest mineral in nature, because of its hardness, if you hit the cleavage plane of diamond, it will break. Therefore, in daily wear, you should be careful to prevent heavy blows. Try not to take it with you at home.