Knowra Mineral Mineral A mineral is a naturally occurring solid with a characteristic chemical composition and ordered crystal structure. Its composition may vary within defined limits.
Crystal structure : The ordered, repeating arrangement of atoms, ions, or molecules in a crystalline solid. Minerals are distinguished from noncrystalline solids by their ordered atomic arrangements.
Crystal system : One of seven categories describing the symmetry and geometry of a crystal lattice. A mineral’s lattice symmetry places its crystals within a characteristic structural system.
Igneous rock : Rock formed when molten magma or lava cools and solidifies. Cooling magma crystallizes many common minerals, with assemblages shaped by melt chemistry.
Ore : Rock or sediment containing valuable materials that can be extracted economically. Some minerals become economically significant when concentrated in mineable ores.
Chemical composition : The identities and proportions of chemical elements in a substance. Mineral names and varieties depend on characteristic compositions and permitted substitutions.
Cleavage (crystal) : The tendency of a crystalline material to break along planes of weak atomic bonding. Directional bonding creates the flat break surfaces used to identify many minerals.
Metamorphism : The transformation of rock through heat, pressure, or chemically active fluids without complete melting. Changing conditions can recrystallize minerals or produce new mineral assemblages.
Gemstone : A mineral or other natural material valued for beauty, rarity, and durability when cut or polished. Selected minerals are prized for optical properties, color, and resistance to wear.
Chemical bond : An interaction that holds atoms or ions together in a substance. Bonding among mineral constituents helps determine structure, hardness, and cleavage.
Mohs scale of mineral hardness : A relative scale ranking minerals by their resistance to scratching. Hardness reflects resistance to disrupting bonds at a mineral’s surface.
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