Katoite is a type of rock that is very special because it is made up of a mineral called calcium hydroxide. This mineral is really important because it is used in things like cement and other construction materials.
Now, calcium hydroxide is actually formed when water reacts with a different mineral called quicklime. Quicklime is made by heating up limestone, which is a type of rock that is found in the ground.
When water mixes with quicklime, it creates a chemical reaction that gives us katoite. Katoite is special because it has a really pretty crystal structure that looks a bit like a snowflake.
So, to sum it up, katoite is a type of rock that is made from a mineral called calcium hydroxide, which is formed when water reacts with quicklime. It's important for making things like cement and has a pretty crystal structure that looks like a snowflake.