Rocks and Landforms Research Project
Obsidian: Black is the most common color seen in obsidian, however it could be brown, tan, or gray. It has a very glassy feel to it.
Diorite: Diorite is mostly speckled black and white. It is medium to coarse grained. Diorite is very hard.
Granite: This rock is very light-colored and has grains large enough that they are visible to the unaided eye. This rock is usually pink, red, grey, or white with dark colored grains.
Basalt: Basalt is a dark-colored and fine grained rock. When broken, the rock is very dull.
Andesite: This rock is usually blue-gray or gray. It is fine grained.
Shale: This rock is dark gray to black. It had very fine grains. It breaks easily.
Schist: Schist is coarse grained, and is generally hard. The color varies between lighter and darker colors. This rock is often shiny.
Gneiss: It is medium to coarse grained and is grey and sometimes pink with dark grains.
Marble: Pure marble is white, although marble can vary in color. The grain size is medium.
Quartzite: This rock usually ranges in light colors. This rock is non-foliated, meaning that it lacks layers, unlike slate.
Shale: This rock is fine grained and consists of many colors in the brown color scheme. This rock is also layered, meaning it breaks easily into different layers.
Breccia: Breccia is the name for a rock that has really large angler particles that are spaced out. Smaller particles close in the space around the large particles. This rock can be coarse or fine grained and can vary in color.
Limestone: This rock is very fine grained and is gray in color.
Amber: This rock comes from tree resin. It is usually yellow or orange in color and is kind of see through.
Coal: Coal is a black rock. It forms from once alive plants.