These things in caves that look like spikes or chandeliers (whether coming up from the ground or down from the ceiling) are called speleothems. Speleothems are found in two forms: stalactites and stalagmites.
You may wonder: "How are these even created?" Well, as usual, science has an answer for this!
These chandeliers first start because there is a cave or cavern in the ground, or a big open space where they can grow. Just like the crystals we talked about last time. When it rains the water travels through cracks in the rock. This water reacts with the rock (normally soluble limestone) and creates calcium bicarbonate or other chemical solutions. When the solution drips through that cracks and into the cave it comes into contact with the air in the cave and solidifies. This creates the stalactite.
Stalactites will often drip solution onto the ground creating a stalagmite. The best way to remember the difference is through their spelling.
|C- Ceiling G- Ground|