Principle purpose of this lecture is to present on Minerals. Minerals are naturally-occurring inorganic substances with a definite and predictable chemical composition and physical properties. There are approximately 4000 different minerals and each of those minerals has a unique set of physical properties. These include: color, streak, hardness, luster, diaphaneity, specific gravity, cleavage, fracture, magnetism, solubility and many more. These physical properties are useful for identifying minerals.