Rock and Landform Project
By: Macy Funk

Igneous Rock

Igneous Rock- Is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rock is formed through the cooling and solidification of magma or lava.


  • Basalt is a dark-colored, fine grained, igneous rock that is composed mainly of plagioclase and pyroxene minerals. It is most commonly crushed for use as an aggregate in construction projects.
  • Granite is a light-colored igneous rock with grains large enough to be visible with the unaided eye. It forms from the slow crystallization of magma below Earth’s surface.
  • Obsidian is an igneous rock that forms when molten rock material cools so rapidly that atoms are unable to arrange themselves into a crystalline structure.
  • Pumice is a light-colored, extremely porous igneous rock that forms during explosive volcanic eruptions. Pumice usually does not have any grains.
  • Rhyolite is an igneous, volcanic rock. Rhyolite has grains that are fine to very fine. Its texture frequently shows altering layers that differ slightly in granularity or color.

Metamorphic Rock

Metamorphic rock is rock that was once one form of rock but has changed to another under the influence of heat, pressure, or some other agent without passing through a liquid phase.


Slate is a naturally-occurring metamorphic rock. It is valued for its ability to break into thin plates.

  • Marble is hard, compact, and has fine or very fine grains. Marble is recrystallized, it is a process that formed from limestone with heat and pressure over years in the earth's crust. These pressure or forces cause the limestone to change in texture and makeup.
  • Quartzite is a hard, metamorphic rock composed mostly of sandstone. The sandstone is converted to quartzite through heating and pressure that is usually caused by tectonic compression. Grains in quartzite recrystallized.
  • Gneiss is a high grade metamorphic rock, meaning that it has been subjected to higher temperatures and pressures than schist.
  • Schist is medium grade metamorphic rock, formed by the metamorphosis of mudstone / shale, or some types of igneous rock, to a higher degree than slate.

Sedimentary Rock


  • Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments.
  • Sandstone is a sedimentary rock formed from cemented sand-sized clasts. The cement that binds the clast can vary from clay minerals to calcite, silica or iron.
  • Coal is an organic sedimentary rock that forms mainly from plant debris. The plant debris usually accumulates in a swamp environment.
  • Halite is the mineral name for the substance that everyone knows as "salt". Its chemical name is sodium chloride and a rock composed primarily of halite is known as "rock salt".
  • Limestone is calcareous sedimentary rocks formed at the bottom of lakes and seas with the accumulation of shells, bones and other calcium rich goods.