List of rock types

The following is a list of rock types recognized by geologists.

There is no agreed number of specific types of rock.

Any unique combination of chemical composition, mineralogy, grain size, texture, or other distinguishing characteristics can describe a rock type.

Additionally, different classification systems exist for each major type of rock.

Some archaic and vernacular terms for rocks are also included.

A sample of andesite (dark groundmass) with amygdaloidal vesicles filled with zeolite . Diameter of view is 8 cm.
Bituminous coal seam in West Virginia
Dolomite crystals from Touissite, Morocco
Turbidite (Gorgoglione Flysch), Miocene, South Italy
Phyllite
Banded gneiss with a dike of granite orthogneiss
Marble
Quartzite
Manhattan Schist, from Southeastern New York
Slate