Classification of Minerals & Rocks (PDF)

# Classification of Minerals ## According to Percentage - **Essential Minerals:** Found in large amounts within a rock, and play a role in determining the rock's name. - **Examples**: - **Exo-Silicates:** - Olivine - Shibole - Mica - Pyroxene - Amphi...

# Classification of Minerals ## According to Percentage - **Essential Minerals:** Found in large amounts within a rock, and play a role in determining the rock's name. - **Examples**: - **Exo-Silicates:** - Olivine - Shibole - Mica - Pyroxene - Amphibole - Mica - Feldspars - Quartz - Calcit - Clay Minerals - **Accessory Minerals:** Found in small quantities within a rock, and do not influence the rock's name. - **Examples**: - Magnetite - Hematite - Pyrite - Garnet ## According to State - **Primary Minerals:** Formed during the original crystallization of the rock, without any change. - **Secondary Minerals:** Formed due to weathering or other processes after the primary mineral has crystallized. ## Chemical Classification - **Elemental:** (e.g. Au, Ag, S) - Halite - **Oxide:** (e.g. Al₂O₃, Fe₂O₃) - Sulfurnite - **Sulfide:** (e.g. FeS₂), Cu₂S - Carbonate - **Carbonate:** (e.g. CaCO₃) - Silicate - **Phosphate:** (e.g. Ca₃(PO₄)₂) - Salt # Gemstone - A mineral that is prized primarily for its beauty and used in cutting and polishing. - **Example:** Diamond # Ore Minerals - Minerals extracted from which specific metals can be obtained. - **Examples:** - Gold - Silver - Iron - Lead # Industrial Minerals - Minerals used for specific industrial purposes. - **Examples:** - Halite - Salt - Gypsum - Cement # The Rock - A natural substance composed of solid crystals of different minerals that have fused together - **Types of Rock:** - **Igneous Rocks:** Formed through the cooling and solidification of molten rock (magma). - **Molten Rock:** liquid formed under high pressure and temperature in deep within the Earth. - **Parent Material:** The source of Igneous rock. - **Lava:** Molten rock flowing on the surface. - **Molten Rocks:** Molten rock beneath the surface - **Volatiles:** Material that easily evaporates when heated, e.g. sulfur, chlorine, etc. - **Sedimentary Rocks:** Formed from the deposition and cementation of sediments. - **Metamorphic Rocks:** Formed from the transformation of existing rocks due to heat, pressure, and chemical reactions. # Acidic Magma - **Characteristics:** - Rich in Feldspars - Rich in SiO2 - Na-K - Poor in Fe, Mg, Ca. - Light in colour with a high viscosity. - Cooling forms Acidic Igneous rocks. - **Crystallization:** The combination of an acidic magma oxide with a basic oxide. # Basic Magma - **Characteristics:** - Rich in Fe-Mg-Ca - Poor in SiO2-Na-K - Dark color with a low viscosity. - Cooling forms Basic Igneous rocks. # Classification of Igneous Rocks - **Occurrence (Origin):** - **Plutonic:** Formed deep within the Earth's crust, where cooling is slow and crystals have time to grow large. These rocks are typically coarse-grained. - **Hypabyssal:** Formed at intermediate depths, with a texture intermediate between plutonic and volcanic rocks. - **Volcanic:** Formed at or near the Earth's surface, where cooling is rapid and crystals are small. These rocks are typically fine-grained. - **Texture:** - **Coarse-grained:** Visible crystals. - **Fine-grained:** Crystals too small to see with the naked eye. - **Chemical and Mineral Composition:** - **Composition:** Determined by the minerals present in the rock. - **Mineral Composition:** The types of minerals which make up the rock. # The Difference is in - **Location:** - Plutonic igneous rocks are formed at depth. - Volcanic igneous rocks are formed on the surface. - **Temperature and Cooling Rate:** - Slow cooling allows for the formation of larger, more easily visible crystals, as seen in plutonic rocks. - Rapid cooling, as in volcanic rocks, leads to smaller, often microscopic crystals. - **Crystal Size:** - Plutonic rocks have larger crystal sizes than volcanic rocks.