Defining a Mineral
In geology, a mineral is a naturally occurring, inorganic solid with a definite chemical composition and a characteristic internal atomic structure, known as a crystalline lattice. These five criteria—natural occurrence, solid state, inorganic nature, specific chemical formula, and ordered atomic arrangement—must all be met for a substance to be classified as a mineral.
Key Characteristics and Structure
Beyond being a solid and naturally formed, minerals are inorganic, meaning they don't originate from living organisms or their remains. Their definite chemical composition means they can be represented by a specific chemical formula (e.g., NaCl for halite). Crucially, minerals possess a crystal structure, where atoms are arranged in a precise, repeating three-dimensional pattern, giving each mineral unique physical properties like hardness, cleavage, and crystal shape.
Common Examples and Their Practical Uses
Quartz, with its silicon dioxide (SiO₂) composition, is one of Earth's most abundant minerals, commonly used in glassmaking and electronics. Feldspar (e.g., KAlSi₃O₈) is another widespread mineral used in ceramics. Halite (NaCl), known as rock salt, is vital for human consumption and industrial processes. Diamond, a pure carbon mineral, is prized for jewelry and used in cutting tools due to its extreme hardness.
Importance in Earth Science and Industry
Minerals are fundamental to understanding Earth's composition, processes, and history. They are the building blocks of rocks and provide essential raw materials for modern society, ranging from construction materials to components in electronic devices and fertilizers in agriculture. Studying minerals helps us locate valuable resources, comprehend geological phenomena, and develop new technologies.