A dodo egg is a renewable food item that is randomly left behind by a dodo bird. Dodo eggs are large and oval in appearance with a light blue shell with a wavy pattern or darker areas.
As a result, rocks form quickly and mineral crystals are very small. Rhyolite is one type of rock that is formed when lava cools. It contains similar minerals to granite. However, as you can see in Figure 3.21, the mineral crystals are much smaller than the crystals in the granite shown in Figure 3.20.
Minerals are: 1) naturally occuring 2) inorganic 3) solids with 4) definite chemical compositions and 5) an orderly arrangement of atoms. There are over 2000 different minerals. A few common  rock-forming minerals  make up most of the rocks in earth's crust, and most of these (over 90 percent) are silicates.The minerals are grouped based on their chemical composition. few common  rock-forming minerals  make up most of the rocks in earth's crust, and most of these (over 90 percent) are silicates. The minerals are grouped based on their chemical composition.