Are there any types of rocks other than igneous, sedimentary and metamorphic rocks?

Expert Answers

An illustration of the letter 'A' in a speech bubbles

All the different rocks found on the Earth are divided into three primary categories: igneous, sedimentary and metamorphic. All other smaller categories of rocks fall into one of these larger categories.

Igneous rocks are created by the cooling of magma which is a liquid found below the Earth's crust. Igneous...

Unlock
This Answer Now

Start your 48-hour free trial to unlock this answer and thousands more. Enjoy eNotes ad-free and cancel anytime.

Start your 48-Hour Free Trial

All the different rocks found on the Earth are divided into three primary categories: igneous, sedimentary and metamorphic. All other smaller categories of rocks fall into one of these larger categories.

Igneous rocks are created by the cooling of magma which is a liquid found below the Earth's crust. Igneous rocks are gradually degraded by elements of the atmosphere like wind, water, etc. The resulting particles form rocks that lie in the category of rocks known as sedimentary rocks. Metamorphic rocks are formed when sedimentary, igneous or other metamorphic rocks are subjected to high pressures and temperatures. This changes the constituents of the original rocks and lead to chemical and physical changes which creates another class of rock.

Approved by eNotes Editorial Team