geology

• Mineralogy


  The branch of geology that deals with the study of minerals, their composition, structure, properties, and the processes that lead to their formation
• Mineralogy involves identifying and categorizing minerals based on their chemical composition and physical properties, as well as investigating their occurrence and distribution in nature
• Objectives of mineralogy


  • Study of the physical properties of minerals
  • Study of rock forming minerals
  • Elementary knowledge on symmetry elements of crystallographic systems

  
• Rock forming minerals


  • Quartz
  • Feldspar
  • Mica
  • Calcite
  • Olivine
  • Pyroxene
  • Amphibole
  • Clay Minerals
  • Garnet

  
• Quartz


  Silicate mineral composed of silicon and oxygen atoms, often forms in igneous, metamorphic, and sedimentary rocks

  
• Feldspar


  Group of aluminosilicate minerals including potassium feldspar, sodium feldspar, and calcium feldspar, essential components of many igneous and metamorphic rocks

  
• Mica


  Sheet silicate minerals including muscovite and biotite, have perfect cleavage and are common in metamorphic rocks

  
• Calcite


  Calcium carbonate mineral, common in sedimentary rocks like limestone and in metamorphic rocks
• Olivine


  Mineral composed of magnesium, iron, and silicate, common in the Earth's mantle and in mafic igneous rocks like basalt

  
• Pyroxene


  Silicate minerals with single-chain tetrahedral structures, common types include augite and diopside, found in igneous and metamorphic rocks

  
• Amphibole


  Group of silicate minerals with double-chain tetrahedral structures, common examples include hornblende and actinolite
• Clay Minerals


  Include kaolinite, montmorillonite, and illite, common in sedimentary rocks and play a significant role in soil formation
• Garnet


  Group of silicate minerals with various compositions, commonly found in metamorphic rocks

  
• Minerals in the quartz family, feldspar family, and other key minerals


  • Quartz
  • Feldspar
  • Augite
  • Hornblende
  • Biotite
  • Muscovite
  • Calcite
  • Garnet

  
• Mirror Plane (σ)


  A flat surface across which reflection occurs, resulting in a mirror image
• Rotation Axis (Cn)


  An imaginary line around which a crystal may be rotated by a certain angle to coincide with its original position
• Inversion Center (i)


  A point in space where all points have their positions inverted relative to that center
• Improper Rotation (Sn)


  A combination of a rotation with a reflection in a plane perpendicular to the rotation axis
• Glide Plane (n)


  A symmetry element that combines reflection across a plane with translation parallel to the plane
• Screw Axis (n)


  A symmetry element that combines rotation about an axis with translation along the axis
• These symmetry elements play a crucial role in determining the overall symmetry and properties of crystals

  
• Crystallographers use these symmetry elements to describe and classify crystals based on their symmetry operations

  
• Color


  The color of a mineral can vary, but it is not always a reliable identifying factor since some minerals can exhibit different colors due to impurities
• Luster


  The way light reflects off the surface of a mineral, can be metallic (shiny and reflective like metal) or non-metallic (glassy, pearly, silky, dull, etc.)
• Hardness


  A measure of a mineral's resistance to scratching, the Mohs scale ranks minerals from 1 (softest, talc) to 10 (hardest, diamond)
• Cleavage and Fracture


  Cleavage is the tendency of a mineral to break along planes of weakness, producing flat surfaces. Fracture is the way a mineral breaks when it does not have cleavage.
• Streak


  The color of the powdered form of a mineral, determined by rubbing the mineral against an unglazed porcelain plate
• Density


  The mass of a mineral per unit volume, often measured in grams per cubic centimeter (g/cm³)
• Crystal Form


  Many minerals have a characteristic crystal structure or form, which can be observed in well-formed crystals

  
• Transparency


  Minerals can be transparent, translucent, or opaque, allowing varying degrees of light to pass through them
• Magnetism


  Some minerals exhibit magnetic properties, either attracting or repelling magnets
• Taste and Odor


  Some minerals may have distinctive tastes or odors, but tasting minerals is not recommended due to potential toxicity
• Double Refraction


  Certain minerals have the property of double refraction, where light passing through them is split into two rays
• Minerals


  • augite
  • hornblende
  • biotite
  • muscovite
  • calcite
  • garnet
• Hornblende


  • Amphibole mineral with monoclinic crystal structure
  • Commonly dark green to black in color
  • Occurs in igneous and metamorphic rocks
  • Characterized by cleavage and elongated crystal habit

  
• Biotite


  • Mica mineral with monoclinic crystal structure
  • Typically dark brown to black in color
  • Occurs in igneous and metamorphic rocks
  • Known for perfect cleavage and thin, flexible sheets

  
• Muscovite


  • Mica mineral with monoclinic crystal structure
  • Usually light-colored, ranging from white to silver to brown
  • Occurs in igneous, metamorphic, and sedimentary rocks
  • Exhibits perfect cleavage and thin, flexible sheets

  
• Calcite


  • Carbonate mineral composed of calcium carbonate (CaCO3)
  • Has trigonal crystal structure
  • Occurs in a variety of colors
  • Found in sedimentary rocks like limestone and marble, as well as in hydrothermal veins

  
• Garnet


  • Group of silicate minerals with various compositions
  • Typically have a cubic crystal structure
  • Come in a range of colors including red, green, and brown
  • Occur in metamorphic rocks like schist and gneiss, as well as in some igneous rocks

  
• Physical properties of minerals

  • Color
  • Hardness (Mohs scale)
  • Cleavage
  • Fracture
  • Specific gravity
  • Luster (metallic, vitreous, pearly, etc.)
  • Crystal habit (shape)