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.
For example, a sedimentary rock form is limestone that is composed only of the mineral calcite. Main rocks on earth contain minerals like magnetite, quartz, feldspar, mica, epidote etc. But more than half of the mineral types classified in geological studies are considered rare.