1. Cleavage: Cleavage refers to the tendency of a mineral to break along specific planes of weakness within its crystal structure. This is directly related to the arrangement of atoms in the crystal lattice. For example, halite (NaCl) has perfect cubic cleavage due to its cubic crystal structure, while mica has excellent cleavage in one direction due to its layered structure.
2. Hardness: Hardness is a measure of a mineral's resistance to scratching. It is determined by the strength of the chemical bonds between the atoms in the crystal lattice. Minerals with strong, tightly-packed structures (like diamond) are very hard, while those with weaker bonds (like talc) are soft.
3. Fracture: Fracture describes the way a mineral breaks when it does not cleave. The pattern of fracture is influenced by the mineral's crystal structure. For example, a mineral with a cubic crystal structure might fracture with a conchoidal (shell-like) pattern, while one with a fibrous structure might have a splintery fracture.
