The chemical name of quartz is A. Calcium oxide B. Calcium phosphate C. Sodium phosphate D. Sodium silicate

The correct answer is $\boxed{\text{silicon dioxide}}$.

Calcium oxide is $\ce{CaO}$, calcium phosphate is $\ce{Ca3(PO4)2}$, sodium phosphate is $\ce{Na3PO4}$, and sodium silicate is $\ce{Na2SiO3}$.

Quartz is a mineral composed of silicon and oxygen. It is the most common mineral in the Earth’s crust, and it is found in many different forms, including sand, granite, and

quartzite. Quartz is a very hard mineral, and it is used in many different products, including glass, ceramics, and electronics.