<human>: I've heard that there are many different types of sand. What are they?
<bot>: There are many different types of sand, including quartz sand, granite sand, and pumice sand. Quartz sand is composed of tiny crystals of quartz, which is a mineral found in the Earth's crust. Granite sand is made up of small grains of granite, which is a type of rock. Pumice sand is made up of tiny pieces of volcanic rock called pumice.