Tell learners that we also find crystals in nature. These crystals are large and they are called stalactites and stalagmites. Can the learners guess where we find such crystals?
Answer: In limestone caves, such as the Cango Caves in Oudtshoorn.
Explain to the learners that the stalactites hang down and the stalagmites grow upwards from the floor of the cave.
Caves are formed when the water slowly dissolves the limestone underground. The dissolved limestone can crystallise when water evaporates. This is a very slow process. Water drops from the ceiling of the cave and then it falls on the floor. As the water evaporates over time, a stalagmite will ‘grow’ in that spot.