4. This is the first sample that I picked up. I think that this rock belongs to the igneous group. Granite is the actual name of this rock. After doing research and after reading the chapter about igneous rocks I learned that this rock forms when cooling pockets of magma is trapped beneath the earth’s surface. This type of rock is usually used for long lasting monuments and for trim and decoration buildings. Granite is a coarse-grained rock that is composed of about 25 percent quartz and 65 percent of feldspar. Granite also consists of quartz crystals, which are roughly spherical in shape and are often glassy and clear to light gray in color. This rock’s texture phaneritic.
5. I categorized my second sample in the metamorphic group. This rock is marble. Marble is a non-foliated metamorphic rock that is produced from the metamorphism of limestone. Marble is composed primary of calcium carbonate. This rock is pure white. These rocks are used to create monuments and statues. Its composition of calcium carbonate cause it to weather when exposed to acid rain. The texture is smooth at some angles and very sharp at others. This rock is shinny when put under direct light.
6. My third sample is from the igneous group. This rock contains a vesicular texture. These types of rocks are full of bubbles. It indicates that it is a volcanic rock. Scoria is a lightweight extrusive rock. This rock has very distinctive gas bubbles and a darker color compared to pumice. This rock is considered a product of basaltic low silica lavas than of felsic high-silica lavas. This is due to basalt usually being more fluid than felsite, which allows bubbles to grow larger before it freezes. This forms as the crust on lava flows that crumbles off as the flow moves. Eruptions can cause it to be blown out of the crater. This texture usually has broken connected bubbles and does not float in water.
7. This rock sample belongs to the sedimentary group. Sedimentary rocks are formed in places where water once existed in the area. This rock has many layers and that is why you can see many streaks of different colors. Some of these rocks contain fossils and other clues about the geologic past.
8. My last and final sample belongs in the igneous group. This is a diorite. Diorite is a coarse grained igneous rock. This is considered an extrusive rock. The texture of this rock is pretty rough all around. This rock has shinny little particles. The texture of this is small grained texture from small crystal size. It has a black and white color to it. The black parts are amphibole and the light areas are made out of feldspar grains.
