* They are not naturally occurring. Minerals form through geological processes over time. Cement, brick, steel, and glass are all manufactured products.
* They don't have a defined chemical composition. Minerals have a specific chemical formula that determines their properties. Cement, brick, steel, and glass are mixtures of different materials with varying compositions.
* They lack a crystalline structure. Minerals are arranged in a highly ordered, repeating pattern of atoms called a crystal lattice. The components of cement, brick, steel, and glass are not arranged in this way.
In short, minerals are naturally occurring, solid substances with a defined chemical composition and a crystalline structure. Cement, brick, steel, and glass do not meet these criteria.
