Rocks and Minerals – The Elementary Study
Let’s start with the very basics of the study. All matter (for example rocks and minerals) is made up of particles called atoms. Certain atoms form elements and the universe is made up of just over 100 elements, which stand-alone or with other elements, form compounds. The earth is made up of 8 elements. The earth’s interior is always changing because of heat and pressure. These changes in the earths crust cause rocks to form. This is a very well balanced system as the interior of the earth is under pressure and intensified heat; the outside elements also play a big factor in cooling the earth down.
Rocks are formed and identified in one of three categories. Those categories are called igneous, sedimentary and metamorphic. Let’s look at the difference in the three.
Igneous – These types of rocks are formed when molten rock (lets call it liquid rock or magma) from deep within the surface is forced out through an opening in the surface of the earth like a volcano. Once it hits the earth’s cool air or water it immediately cools and hardens.
Sedimentary -These rocks are formed at the earth’s surface when wind, water and the weather have a direct effect on them. Through erosion, pieces of sand, soils and little pieces of rocks settle together and form layers and then harden. These layers can be seen in the rock, itself making it easily identifiable.
Metamorphic -These types of rocks are formed when extreme pressure from the inside and outside of the earth causes the shifting and changes in the other two categories of rocks (igneous and sedimentary). This type of rock looks like they have been squeezed or folded together.
Rocks and minerals are not the same thing though. They both have very specific properties. Looking at and studying those properties will help determine if what is being identified is either a rock or a mineral. The following properties are a few ways to determine the difference.
Luster is a property to show how light is reflected on the surface and how it is perceived. Whether it is shiny or dull begin the identification and starts to point in the direction of “rock vs. mineral”.
Hardness is another property that can show how much a rock or mineral resist from being scratched.
Cleavage is yet another property that shows how a mineral splits along a plane when it is hit at a part of its structure.
Finally a streak test can be administered which means that the rock or mineral is rubbed across a surface to identify the color of the streak.
From collecting, to understanding atoms, to forming compounds is just the beginning to understand the world as a whole and it’s formation. Continue to follow along with this study in the weeks to come.
