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.
Four major types of limestone formations (speleothems): 1  Dripstones: 2  Straws are thin walled hollow formations that resemble drinking straws. As water drips slowly from the roof of the cave, it deposits a microscopic ring of calcite crystal. 3  Stalactites are also formations that grow downwards from the cave roof.