Quartz is one of the most useful natural materials. Its usefulness can be linked to its physical and chemical properties. It has a hardness of seven on the Mohs Scale which makes it very durable. It is chemically inert in contact with most substances. It has electrical properties and heat resistance that make it valuable in electronic products. Its luster, color, and diaphaneity make it useful as a gemstone and also in the making of glass.
Flint: Flint is a variety of microcrystalline or cryptocrystalline quartz. It occurs as nodules and concretionary masses and less frequently as a layered deposit. It breaks consistently with a conchoidal fracture and was one of the first materials used to make tools by early people. They used it to make cutting tools. After thousands of years, people continue to use it. It is presently used as the cutting edge in some of the finest surgical tools. This specimen is about four inches (ten centimeters) across and is from Dover Cliffs, England.
