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 substances that are formed naturally in the Earth. Minerals are usually solid, inorganic, have a crystal structure, and form naturally by geological processes. The study of minerals is called mineralogy. A mineral can be made of single chemical element or more usually a compound. There are over 4,000 types of known minerals.