ROCK

ROCK

Lithosfer nor crust consists of rocks. Rock has a broad meaning and differ with stones. 

Rock is the material that forms lithosfer or crust, composed of the minerals, are formed in nature and not live. Can be formed from only one set of various kinds of mineral or minerals. Both are compressed or not. For example clay, though not hard or mushy, but are formed in nature and consist of minerals (very fine grained), including rock. Instead of trees, hard and form in nature, but to live and not from the minerals, it does not include rock. While the stone, in the sense of the everyday is a hard lump. In geology a complementary word that gives a solid understanding and hard which is the result of a geological process. For example, sand dust, after experiencing the process of stone-sand litifikasi become dense and hard. Physical properties far different from the original material.

Studying rocks is a knowledge base for studying geology. By studying the rocks we can know the nature and history of our earth.

In the recorded rock geological processes that have occurred during the formation of rocks.

For example from the fossil in sedimentary rocks can be known environment where and when the rock was deposited and formed. And of magnetism that are stored in igneous rocks, which affected the Earth's magnetic field during freezing, can be studied polarization of the earth's magnetic field millions of years ago. And age can be determined by performing radioactive against these igneous rocks.

We have encountered a variety of rocks around us. Judging from their physical properties are very diverse, good color, hardness, cohesiveness, and its constituent materials. To make it easier to distinguish, made grouping or classification.

The simplest grouping is based on what happened or how the formation, or genesis into three main groups:

1. Igneous rock, formed from magma that cools and solidifies.

2. Sedimentary rock is rock formed from sediments deposited (on land or in water) and after experiencing geological processes into sedimentary rocks.

3. Metamorphic rocks or metamorphic rocks. Rocks, which have undergone changes in pressure and or high temperatures. Conversion into Metamorphic rocks, or metamorphic rocks without melting.