Concept in Definition ABC

Rock is known as a material that is formed by a set, whether consolidated or not, of defined minerals and which are the ones that are naturally made of the mantle and the Earth crust and also the equivalents of other earth-like planets.

The rocks can be composed of several species of minerals (composite rocks) or by a single one (monominerálicas rocks). Rock is mostly a very hard material, although some soft ones can also be found, such as clay rocks and sand.

As we said at the beginning, the earth's crust is made up of rocks and at this time we can distinguish between three types: igneous rocks, which are those that are formed by the solidification of lava, metamorphic rocks, which were formed by the alteration in solid state of rocks already consolidated in the earth's crust, that is, they were subjected to a environment energetic very different from your training and finally the sedimentary ones, which were formed thanks to the consolidation sediments, which are materials from the erosion from previous rocks.

A characteristic feature of rocks is that they are always subject to changes as a consequence of the geological agents that modify them, such as the mentioned erosion, weathering and sedimentation.
On the other hand and based on the fact that the material that makes up the rocks preeminently is very hard, the term rock is used also in other contexts when you want to give an idea of ​​the hardness and consistency of a thing, object or person.

For example, when a person always or occasionally observes a conduct determined and rigid that does not give rise to even the slightest opinion of the other, then, it is customary to say that that person is hard.