What Is a Schist Made of?

Identification

• Schist is a crystalline rock that is typically identified by flaky layers, according to the California Polytechnic University at Pomona. Schists are formed under comparatively low heat and pressure, making the rough crystalline structure identifiable to the naked eye.

Types

• According to the National Geological Survey, schist rocks are named for the type of mineral that makes up the largest part of their composition. For example, a talc schist is composed of a variety of minerals but is largely made of talc. Other common examples are mica schist, biotite schist, chlorite schist and graphite schist.

Uses

• Schists are not commonly used as building stones because they are weak. Because of the colors often present in the rocks, however, they are often make into stone flooring or put to other decorative nonweight-bearing purposes.