1. Quartz: Used in watches, electronics, and glassmaking. Quartz crystals are piezoelectric, meaning they generate an electrical charge when pressure is applied, making them ideal for timekeeping and other applications.

2. Hematite: Used in pigments, jewelry, and as a source of iron. Hematite is a naturally occurring iron oxide and is responsible for the red color of many soils and rocks.

3. Halite (Rock Salt): Used for de-icing roads, preserving food, and as a source of salt for cooking and other purposes. Halite is a naturally occurring form of sodium chloride, the common table salt.