You might have been doing rock collecting for some time now. Your collection probably has grown, not the best you will admit but still a decent one. But do you remember the first few attempts you had with rock collecting? Looking back, everything was not as good and as easy as today, was it? You did not know squat back then, even the basic types of rocks you find confusing. Now knowing the different kinds of rocks is essential for this hobby, of course, so let’s help those starting out with a few definitions and probably some stories to spark their interest.

Geologists were kind enough to divide the different kinds of rocks according to how they were formed. Basically, these groups are the igneous, the sedimentary and the metamorphic rock groups. Each group has its own unique characteristic which you, as a rock collector, should seriously learn and know about. Finding rock samples is good, but finding good unique ones can make your collection from simple to a simply awesome one.

Rocks down within the Earth melt because of the high pressure and the extremely high temperature. The molten rock is called magma and is actually what we see coming out of volcanoes. As magma climbs out of the Earth, the liquid rock cools down. And when it cools, it creates crystals. The more rapidly the magma cools down, the smaller the crystals formed. The bigger the crystals, the coarser the rock formed, and the smaller they are, the finer the rock formed. Good examples of igneous rocks include obsidian or volcanic glass, granite, basalt and andesine porphyry.

Unlike igneous rocks, sedimentary rocks are formed on the surface of the Earth and did not begin in a melted state. Sedimentary rocks are formed from layers of accumulated matter such as rocks, minerals and even plant and animal materials. Pressure and temperature still play a vital role in forming this kind of rock. There are sedimentary rocks that have been cemented together by minerals and chemicals while there are others that are still loose.

Metamorphic rocks, on the other hand, are formed from either igneous or sedimentary. This time, extremely high pressure or temperature will change the rocks altogether. The pressure and heat makes the rocks denser and even changes the minerals within. The process does not melt the igneous or sedimentary rocks, however. These kinds of rocks are found deeply buried underneath the Earth.

Knowing the different types of rocks is only half the battle. But still, learning them by hearth will help you greatly in coming up with a great collection. Knowing what kinds of rocks are there and where to find them will help your collection grow immensely.

Related posts:

1. You Should Learn Know How to Identify Rocks Before You Start Rock Collecting
2. Telling the Earth’s Story Through Rock Collecting
3. There Are Different Types of Rocks for Those Who Pursue
4. Know how to identify your rock collection specimens
5. Rock collecting can be addictive