Different types of rocks

Did you know that rocks are not all the same?
Their classification depends on the ways in which they originated.
There are three main types of rocks:

• Sedimentary
• Metamorphic
• Igneous

Sedimentary rocks can be defined a “second generation rocks”. In fact, they derive from the deposition of mineral substances from other rocks that have undergone a previous physical or mechanical degradation. The process that compacts and crystallizes sediments is named diagenesis.
The study of these rocks is interesting also because of the high probability to see the presence of fossils, which provide essential information about the history of life on Earth. An example of this type of rock is the limestone.

Metamorphic rocks are the ones that have undergone mechanical or chemical transformation processes by the pressures and temperatures involved in the strong geological phenomena. However, they don’t suffer the complete fusion of their minerals. An example of this type of rock is the marble.

Finally, igneous rocks derived from the solidification of magma, a complex mixture of high temperature mineral substances, water vapor and gases coming from the depths of the Earth. When lava cools rapidly, there is the creation of these shiny and glasslike rocks (e.g. basalt and obsidian).