Rocks

By: Abishek Balakrishnan

Rock Cycle

Sedimentary can become metamorphic rock, or sediments depending on the process. Igneous can become magma, metamorphic rock, or sediments depending on the process. Metamorphic can become magma, or sediments depending on the process. Magma must become igneous (cooling), while sediments must become sedimentary (compaction and cementation).

Sedimentary Rock (Iron Ore)

  • chemical sedimentary rock
  • formed when iron and oxygen combine in solution and deposit as a sediment
  • most common sedimentary iron ore mineral is hematite

  • found in China, Australia, Brazil and India

Igneous Rock (Diorite)


  • coarse grained
  • intrusive igneous rock
  • composition similar to andesite
  • composed mainly of plagioclase feldspar, amphibole, and pyroxine minerals with small amounts of biotite mica
  • abundant white and dark minerals
  • formed when magma (that never made it to surface) cools
  • forms from magma that doesn't contain a lot of quartz or the light colored minerals (that make up granite)
  • found in Sondrio (Italy), Thuringia and Sassonia (Germany), Finland, Romania, central Sweden, Scotland, the Andes Mountains, Basin and Range province, and Minnesota (USA)


Metamorphic Rock (Novaculite)

  • dense
  • hard
  • fine- grained
  • siliceous rock
  • breaks with a conchoidal fracture
  • formed from sediment deposits in marine environments where organisms such as diatoms are plentiful in the water. After death, the diatoms’ silicon dioxide shells fall to the seafloor. During a transformation from sediment to rock, diagenesis, the silicon dioxide from the shells is transformed into a chalcedony. This rock is chert, and as further diagenesis and low grade metamorphism recrystallizes the chalcedony into microcrystalline quartz grain, it transforms into novaculine.


  • found in Ouachita Mountains (Arkansas), Texas, and Oklahoma