Medical Definition of amnesia. 1: loss of memory sometimes including the memory of personal identity due to brain injury, shock, fatigue, repression, or illness or sometimes induced by anesthesia a period of amnesia after the wreck.
Shale is a fine-grained sedimentary rock that forms from the compaction of silt and clay-size mineral particles that we commonly call mud. This composition places shale in a category of sedimentary rocks known as mudstones.
Igneous Rock Types: Basalt, Granite, and More. Igneous rocks are classified by the minerals they contain. The main minerals in igneous rocks are hard, primary ones: feldspar, quartz, amphiboles, and pyroxenes (together called dark minerals by geologists), and olivine along with the softer mineral mica. The two best-known igneous rock types are basalt and granite, which have distinctly different compositions and textures.