Coal and Obsidian Definition

Definition of Coal and Obsidian

The general Coal and Obsidian definition can be stated as: Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers called coal beds. On the other hand, Obsidian is a naturally occurring volcanic glass formed as an extrusive igneous rock. It is produced when felsic lava extruded from a volcano cools rapidly with minimum crystal growth. Along with definition of Coal and Obsidian, get to know about Properties of Coal and Obsidian. Get to know more information about Coal and Obsidian origin and discoverer, etymology and class.

History of Coal and Obsidian

The history of Coal and Obsidian gives information about where the rock was found and who was its discoverer. Almost each and every aspect of Earth's history is recorded in rocks be it the volcanoes which were erupted or the plants, animals and organisms which are now extinct, as rocks are present from millions of years.

Coal and Obsidian Origin and Discoverer

Coal and Obsidian definition gives us a brief idea about the two rocks. In some cases, the definition also gives summary about the Formation of Coal and Obsidian. In this section, you will know about Coal and Obsidian Origin and Discoverer. Origin of Coal is USA whereas Origin of Obsidian is Ethiopia. It is interesting to know the name of Coal and Obsidian discoverer. The Discoverer of Coal is John Peter Salley and the discoverer of Obsidian is Obsius.

Etymology of Coal and Obsidian

Along with Coal and Obsidian definition, know more about the etymology of Coal and Obsidian. Etymology of Coal and Obsidian gives information about origin and formation of a particular rock. Know more about Formation of Coal and Formation of Obsidian. The etymology of Coal is From the Old English term col, which has meant mineral of fossilized carbon since the 13th century while that of Obsidian is From the Old English term col, which has meant mineral of fossilized carbon since the 13th century. The process of formation of rocks defines the class of rock. All the rocks in a class are formed by similar processes. Coal belongs to Sedimentary Rocks while Obsidian belongs to Igneous Rocks. The sub-class, group and other categories of Coal and Obsidian are listed below.

For Coal,

• Sub-class: Durable Rock and Soft Rock
• Group:
• Other Categories: Coarse grained rock, Fine grained rock, Medium grained rock and Opaque rock

For Obsidian,

• Sub-class: Durable Rock and Medium Hardness Rock
• Group: Volcanic
• Other Categories: Opaque rock