Rock collecting can be one of the most fun and interesting activities that can be done with a family, with children, or simply alone. For one thing, there are rocks everywhere. The key to collecting rocks, especially for the beginner, is to collect rocks that you like to look at and will make your collection interesting.
It is important to have a basic knowledge about the rocks that you are collecting. Generally, it is important to know that there are three types of rocks igneous, sedimentary, and metamorphic. Igneous rocks are formed from cooling lava or magma. Intrusive igneous rocks usually form underground from and tend to have larger crystal formations. A popular example of intrusive igneous rock is granite, with its variegated color formation and large crystal formation. Extrusive igneous rock, on the other hand, cools much quicker and are a result of lava cooling above the earth. Common extrusive igneous rocks are basalt and pumice which both have smooth tight crystal formations that are often difficult to see with the naked eye. One important thing to understand is that magma is the term used for molten rock underground and lava is the term used for molten rock once it erupts above the earth. Igneous rock is the product of this molten rock.
Sedimentary rock is one of the most common types of rock found on earth. Sedimentary rocks are formed as a result of weathering from wind and water, erosion, and precipitation from a solution. The most commonly known sedimentary rocks include limestone, chalk, sandstone, conglomerate, and shale. As the rocks are broken in to sediments, they are then compacted and cemented together through the process of lithification. Sedimentary rocks can stay within the rock cycle as various forms of sedimentary rock for millions of years due to the commonality of the weathering and erosion process.
Metamorphic rock must have heat and pressure in order to be formed. Common examples of metamorphic rock are gneiss, slate, marble, schist, and quartzite. Because of the pressure involved in making metamorphic rock, layers are often a significant part of metamorphic rock. The key is that the rocks are deep formed below the earth’s crust. The layer formed within this type of rock is known as foliation which happens when rocks are compressed in one direction during the crystallization process.
As an ingnue rock collector, look for rocks that are interesting to you. Much of your collection will be determined by where you live or where you visit. No matter where you go, there are going to be rock, so always keep zipper bags close at hand to slip a couple samples in for your collection. If you live on the Texas Gulf Coast, you will probably find and abundance of sedimentary rocks. If you are visiting Hawaii or any other location that is close to volcanic activity, you are likely to find an abundance of igneous rocks. Metamorphic can be a little trickier to find since they are formed under the earth. A rock quarry visit might be a good place to visit to add to your collection.
As with any type of collecting, it is important to just have fun. Learn as much as you can about what you are collecting and your collection is sure to give you many years of enjoyment. With rock collection get yourself some good easy to read geology books that will help you better understand the rock cycle and the actual rock formation process. Get to know your rocks and you are guaranteed fun for the years to come.