Formation
Due to change in environmental conditions, rocks are heated and pressurized deep inside the Earth's surface. Skarn is formed from the extreme heat caused by magma or by the intense collisions and friction of tectonic plates.
  
Coal forms from the accumulation of plant debris in a swamp environment which is buried by sediments such as mud or sand and then compacted to form coal.
  
Composition
  
  
Mineral Content
Calcite, Enstatite, Epidote, Garnet, Magnetite, Pyroxene, Titanite
  
Analcime, Apatite, Barite, Calcite, Chalcopyrite, Chlorite, Chromite, Clausthalite, Clay Minerals, Crandallite Group, Dolomite, Feldspar, Galena, Gypsum, Marcasite, Muscovite or Illite, Pyrite, Quartz, Siderite, Sphalerite, Zircon
  
Compound Content
Au, CaO, Carbon Dioxide, Cu, Fe, MgO
  
Carbon, Hydrogen, Nitrogen, Oxygen, Sulphur
  
Transformation
  
  
Metamorphism
Yes
  
Yes
  
Types of Metamorphism
Burial Metamorphism, Cataclastic Metamorphism, Contact Metamorphism, Hydrothermal Metamorphism, Impact Metamorphism, Regional Metamorphism
  
Burial Metamorphism, Cataclastic Metamorphism, Regional Metamorphism
  
Weathering
No
  
No
  
Types of Weathering
Not Applicable
  
Not Applicable
  
Erosion
No
  
No
  
Types of Erosion
Not Applicable
  
Not Applicable
  
Skarn and Coal Formation
Formation of rocks is a long process and hence, Skarn and Coal formation sounds very interesting. According to the formation, all rocks are divided into :Igneous Rocks, Fossil Rocks and Metamorphic Rocks. Igneous rocks form by crystallization of magma or lava. The magma is made up of various components of pre-existing rocks which have been subjected to melting either at subduction zones or within the Earth's mantle. Igneous rocks are generally seen at mid ocean ridges or in intra-plate hotspots. Sedimentary rocks are formed when sediments accumulate gradually. As the sediments are buried they get compacted as more and more material is deposited on top. Eventually the sediments become so dense that they form a rock. Metamorphic rocks are rocks which once existed as igneous or sedimentary rocks but have been subjected to varying degrees of pressure and heat within the Earth's crust. Get to know all about formation of Skarn and Coal, composition of Skarn and Coal and their transformation.