malachitePicture of malachite, which is a gemstone and also an important copper ore.

Its crystal structure is shown below:

malachite crystal structure


Carbon - BLACK

Copper - BLUE


Rock cycle index

The Rock cycle

Rock formation

Erosion and weathering

Identification of rocks



Crystal structures of rocks






Tiger eye, below, is a rock that has a very characteristic colour pattern:

(image kindly provided by )

Introduction to the Rock cycle


It is amazing to note that even  those things that seem to last forever have a “life cycle”.

Stars  eventually fade and explode.This is known as the death of a star. Their mass is spread around space and it is  then used as building materials for new stars and planets.

Rocks also are continuously being created and destroyed and the reason why we don't see these  processes occurring is because they take a very long time to occur. The earths crust consisted originally of rocks only and the decomposition of these rocks plus the remnants of dead plants and animals originated the soil. After a long time, soil is buried, squeezed, compressed, heated and finally converted into rock again. Oil may also be formed in this process. Petroleum means stone oil (petra- stone; oleum- oil).

Let's first see how rocks are broken down and them we will see how they reform.