Rocks and Minerals

• Minerals


  Naturally occurring, inorganic, solid element or compound with a definite chemical composition and a regular internal crystal structure
• Types of Minerals

  • Native Elements
  • Sulfides
  • Halides
  • Oxides and Hydroxides
  • Nitrates, Carbonates, and Borates
  • Sulfates, Chromates, Molybdates, Tungstates
  • Phosphates
  • Silicates
• Rocks


  A natural occurring aggregate of mineral materials. All rocks are made of 2 or more minerals, but minerals are not made of rocks. The properties of rocks are important in determining their suitability for particular applications.
• Rock Structure

  • Primary structures - Formed before or at the same as material is in the process of becoming rock
  • Secondary structures - Structures imposed on rock after it has already formed
• Environments of Rock Origin


  • Igneous Rock
  • Sedimentary Rock
  • Metamorphic Rock
• Igneous Rocks


  Form when molten lava (magma) cools and turns to solid rock. They come from the center of the Earth, below the crust.
• Five Kinds of Igneous Rocks

  • Granite
  • Diorite
  • Gabbro
  • Periodotite
  • Pegmatite
• Sedimentary Rocks


  Formed over time as sediments harden and get buried by more sediments. Often have fossils and cover 75% of the Earth's surface.
• Six Main Kinds of Sedimentary Rocks

  • Conglomerate
  • Sandstone
  • Shale
  • Limestone
  • Gypsum
  • Breccia
• Metamorphic Rocks


  Rocks that have changed form due to heat and/or pressure. The least common of the 3 kinds of rocks.
• Two Distinct Types of Metamorphic Rocks

  • Foliated Metamorphic Rocks (e.g. Slate, Schist, Gneiss)
  • Non-foliated Metamorphic Rocks (e.g. Marble, Quartzite, Soapstone)
• Rock Cycle


  The continuous process of rocks being formed, worn down, and then formed again over thousands and millions of years.
• Rock Cycle Process


  1. From Magma to Solidification

  2. Weathering, Erosion, and Lithification

  3. The Transformative Process

  4. From Metamorphic to Magma
• Streak


  when a mineral is rubbed firmly across an unglazed tile of white porcelain (a streak plate), it leaves a line of powder
• Transparency


  describes how well light passes through a mineral sample
• Luster


  the way the surface of mineral reflects light
• Hardness


  • established by the German mineralogist, Friedrich Mohs
• Cleavage


  when a mineral sample is broken with a hammer, it breaks along planes of weakness that are part of its crystalline structure
• Fracture


  can be smoothly curved, irregular, jagged or splintery
• Specific gravity


  the density of a mineral
• Pyrite


  • forms as a cube with fine ridges on the crystal's faces
  • Fool's gold
  • most common sulfide minerals
  • tetragonal and hexagonal
• Beryl


  • common crystal that forms as a six-sided prism
  • used as the main industrial source for beryllium
  • orthorhombic
• Topaz


  • shape like prisms with fine vertical ridges
  • considered a rare and valuable gemstone
  • monoclinic
• Gypsum


  • an evaporite
  • can appear as transparent crystals (selenite); fibrous, elongated crystals (satin par); granular and compact masses (alabaster); and in rosette-shaped aggregates (dessert roses)
  • triclinic
• Crystallography


  division of the entire study of mineralogy
• Native elements


  type of minerals which are elements that occur in nature in uncombined form with a distinct mineral structure.
• Sulfides


  are a class of minerals containing sulfide as the major anion. Some sulfide minerals are economically important as metal ores.
• Halides


  a group of naturally occurring inorganic compounds that are salts of the halogen acids and encompass minerals with a dominant halide anion

  (F−, Cl−, Br−, and I−).
• Oxides and Hydroxides


  these classes consist of oxygen-bearing minerals; the oxides combine oxygen with one or more metals, while the hydroxides are characterized by hydroxyl (OH)– groups.
• Nitrates, Carbonates, and Borates

  Carbonates are transparent, soft, soluble and lightly colored with a white streak. They tend to occur in oxidizing environments, in sedimentary rocks or in carbonatite igneous intrusions. Nitrate is a compound combining the nitrate ion with one or more cations. Borates is any of a range of boron oxyanions, anions containing boron and oxygen.
• Sulfates, Chromates, Molybdates, Tungstates

  The sulfate or sulphate ion is a polyatomic anion. Chromates is a salt in which the anion contains both chromium and oxygen. Molybdate is a compound containing an oxyanion with molybdenum in its highest oxidation. Tungstates is a salt in which the anion contains both tungsten and oxygen.
• Phosphates


  Phosphates is any salt or ester of any phosphoric acid, esp a salt of orthophosphoric acid. Arsenate is a moderate oxidizer and an electron acceptor, with an electrode potential of +0.56 V for its reduction to arsenite. Vanadates is a salt in which the anion contains vanadium and oxygen.
• Silicates


  a salt in which the anion contains both silicon and oxygen.