Where do stones come from?

Question

Everybody knows that stones, rocks, whatever wear down under the influence of weather. But how are they "born"? What's the circle of live for a stone?

Answer 1

It is better to use the term "rock".

A rock is the solid state of molten rock which is known as "magma". Magma is generated from the mantle deep in the Earth. Whenever this magma reaches the Earth's surface, it's called lava. Being exposed on the surface, means lower temperatures, which will make this lava cool down. As it reaches the melting temperature, it solidifies and becomes a rock.

Note: Melting temperatures differ according to the original magma composition. The more iron,magnesium, calcium it has the higher the melting temperature will be. If it has more silica, sodium and potassium, melting temperatures are expected to be lower (around 800 C).

Back to our topic, the resulting rock is called "igneous rock" whenever it solidifies directly from magma/lava. Because this rock is being exposed on the surface, it is subject to weathering, erosion (processes that will break the rock into smaller fragments) and transportation which will transport these small rock particles to another location and be deposited as what we know as sediments.

As other sediments are deposited over and over, they will make a sedimentary rock which is a consolidated form of originally loose sediments due to compaction, cementation and other diagenetic processes.

Note: Sedimentary rocks can be formed of fragments coming from any type of rock whether igneous, sedimentary or metamophic rocks.

The 3rd type of rocks is metamorphic rocks. After deep burial, the rock (any type) is subject to higher temperatures and pressures. this will cause its constituent minerals to be recrystallized to become other stable minerals.

Note: Metamorphism occurs in the solid state of rock. If the rock melts, then crystallizes that means it's an igneous rock.


All these processes are responsible for forming the three types of rocks : Igneous, Sedimentary and Metamoprhic.

This is known as the "Rock Cycle".

Answer 2

Go here;
http://www.minsocam.org/MSA/K12/rkcycle/rkcycleindex.html

Answer 3

stones come from mountains...mountainn r on earth...n the earth is in the solar system...................!!!