handout 4-5

• Mineral


  A solid, inorganic substance of natural occurrence
• Rock


  A conglomerate of various minerals formed on Earth's surface
• Ore


  Naturally-occurring solid where valuable metals and/or minerals extracted for profit
• After the Big Bang, the Universe was made up of hydrogen and some helium. Nucleosynthesis created heavier elements. Young stars form helium out of hydrogen. Later on, helium is converted into heavier elements like carbon, oxygen, silicon, and eventually iron. When a star explodes (either as a nova or as a supernova), they create elements heavier than iron.
• Elements with even atomic numbers are an order of magnitude more common than odd ones.
• Most common elements in our entire planet

  • Oxygen
  • Silicon
  • Iron
  • Magnesium
  • Calcium
  • Aluminum
  • Sodium
  • Potassium
  • Carbon
  • Hydrogen
  • Nickel
  • Sulfur
• Lithosphere


  • The rigid outer part of the Earth's subsystem, consisting of the crust and upper mantle
• Rocks are ever-changing in its form and composition, as shown in the rock cycle.
• Three kinds of rocks

  • Igneous
  • Sedimentary
  • Metamorphic
• Igneous rocks


  Rocks made from the cooling of molten material, such as magma, lava, and other pyroclastics
• Sedimentary rocks


  Rocks made from cementing and compacting eroded materials from other rocks called sediments
• Metamorphic rocks


  Rocks made through the process of metamorphism, where pressure and temperature dictate its new properties
• Formation of igneous rocks by slow cooling

  1. Magma cools slowly to allow the minerals to realign themselves and recrystallize

  2. Resulting rocks have large crystal structures visible to the naked eye
• Igneous rocks formed by slow cooling

  • Granite
  • Diorite
  • Syenite
• Formation of igneous rocks by rapid cooling

  1. Free-flowing lava must be cooled quickly

  2. Resulting rocks are glass-like in appearance and properties

  3. Minerals aren't given enough time to recrystallize, creating minimal mineral crystals that aren't visible to the naked eye
• Igneous rocks formed by rapid cooling

  • Basalt
  • Obsidian
  • Andesite
  • Rhyolite
• Formation of igneous rocks as pyroclastics


  1. Lava is extruded violently from the volcano

  2. Resulting materials can be as small as ash, or large enough to be called rocks (pyroclastic rocks)
• Igneous rocks formed as pyroclastics


  • Ignimbrite (or adobe)
  • Tuff
  • Volcanic breccia
  • Scoria
  • Pumice
• Formation of sedimentary rocks by cementation

  1. Particulates that have been eroded are carried off from faraway sources, then deposited, buried, and undergo compaction and cementation

  2. Combining both compaction and cementation yields lithification, the process that converts sediments into sedimentary rocks
• Clastic rocks


  Sedimentary rocks where the materials are purely mineral in origin, including other large debris caught in the compaction
• Clastic sedimentary rocks


  • Sandstone
  • Shale
  • Conglomerate
• Bioclastic rocks


  Sedimentary rocks where the materials contain any biological remains, such as shells, bones, or trapped resins among others
• Bioclastic sedimentary rocks


  • Coquina
  • Organic limestone
• Formation of sedimentary rocks by chemical precipitation

  1. Sediments precipitate downward from saturated liquids made during the erosion process

  2. If there are minimal foreign inclusions and/or contaminations, they can form rocks made of similar materials, which can be called chemical rocks
• Sedimentary rocks formed by chemical precipitation

  • Halite (salt)
  • Limestone
  • Dolostone
• Formation of metamorphic rocks through pressure

  1. Pressure adds considerable stress on the rocks, increasing heat in the material

  2. The banded "layers" of the various materials of the original rock are revealed

  3. The bands form perpendicularly from the direction of the pressure

  4. The final product is then called a foliated or regional rock due to the bands being called foliation
• Metamorphic rocks formed through pressure

  • Gneiss (made from shale or granite)
  • Schist (made from shale turning to slate, then to phyllite)
  • Slate (made from shale)
• Formation of metamorphic rocks through temperature

  1. The subject rock is exposed to older rock and an intruding body of magma

  2. It may either undergo recrystallization or fundamentally change its mineralogy (if there are chemically-active fluids present)

  3. This process is called contact metamorphism, as the rocks this creates are nonfoliated metamorphic rocks
• Metamorphic rocks formed through temperature

  • Marble (made from limestone)
  • Quartzite (made from quartz-rich sandstone)
• Igneous rock textures


  • Pegmatitic
  • Phaneritic
  • Aphanitic
  • Porphyritic
  • Vesicular
  • Pyroclastic
• Igneous rock compositions


  • Felsic
  • Intermediate
  • Mafic
  • Ultramafic
• Pegmatitic


  Similar to a pegmatite, an igneous rock whose interlocking crystals grow at least 2.5 cm in size and can be found near masses of large igneous rocks (called batholiths)
• Phaneritic


  Rocks that are classified as intrusive rocks
• Aphanitic


  Rocks that are classified as extrusive rocks
• Porphyritic


  Rocks with distinct crystals of various sizes
• Vesicular


  Full of air pockets (called cavities) formed by releasing trapped gas bubbles during solidification
• Pyroclastic


  Rock fragments of volcanic origin pulverized and released during an eruption
• Felsic


  Rocks with light coloration as a result of high silica (SiO2) content
• Mafic


  Rocks with dark coloration as a result of high iron (Fe) and magnesium (Mg) content
• Ultramafic


  Rocks made of mafic minerals