Igneous rocks are rocks created from magma or lava. There are two types of igneous rocks. Intrusive or extrusive. Intrusive is formed under the ground and because it takes so long to cool it has larger grains or what makes up the mineral. Extrusive means it is formed above the ground and because it cools fast it has smaller grains. Now here are some igneous rocks.
1. Pumus
2. Granite
3. Basalt
4. Scoria
5. Obsidian
I will be focusing on obsidian for now. Obsidian is an extrusive rock with a glassy look. It is used for blades in surgery and jewelry. One of the more common uses is that it was used for weapons such as arrow and spear points.
2. Granite
3. Basalt
4. Scoria
5. Obsidian
I will be focusing on obsidian for now. Obsidian is an extrusive rock with a glassy look. It is used for blades in surgery and jewelry. One of the more common uses is that it was used for weapons such as arrow and spear points.