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The earth’s crust consists of rocks. A rock is any mineral material of the earth. It may be a combination of different mineral element such as silica which consists of silicon and oxygen.

TYPES OF ROCKS

There are three major types of rocks. They are:

  1. Igneous rock

  1. sedimentary rock

  1. Metamorphic rock.

IGNEOUS ROCK

Characteristics

  1. They do not contain fossils

  1. they are usually hard and impervious

  1. they are resistant to erosion and other elements of climates

  1. they do not occur in layers

  1. they are crystalline in structure

SEDIMENTARY ROCKS

Characteristics

  1. They occur in layers or strata

  1. they may be coarse, fine soft or hard

  1. they do not exist in crystals

  1. they contain fossils of plants and animals

  1. they are not resistant to erosion

METAMORPHIC ROCK

Characteristics

  1. Some of them occur in layers or strata

  1. the rocks may be hard or soft

  1. they are not crystalline in structure

  1. they exist in different structures and textures

  1. they may contain fossils

DIFFERENCES BETWEEN SEDIMENTARY ROCK AND METAMORPHIC ROCK

  1. Metamorphic rocks are generally resistant than sedimentary rock

  1. metamorphic rocks are crystalline while sedimentary rock are non-crystalline