Glossary

A (6) | B (6) | C (10) | D (11) | E (7) | F (10) | G (10) | H (1) | I (2) | J (1) | L (7) | M (12) | O (3) | P (11) | Q (3) | R (9) | S (23) | T (5) | U (3) | W (1)

Alluvium

Clay, silt, sand, gravel, or similar unconsolidated detrital earthen material deposited during relatively recent geologic time by a stream or other body of running water. Alluvium usually contains rounded particles and usually collects in the channels and floodplains of creeks, streams, rivers, and lakes.

Amphibole

A group of generally dark hydrous silicate minerals including common rock-forming varieties, such as hornblende and actinolite.

Amphibolite

A type of dark metamorphic rock consisting mainly of amphibole and plagioclase feldspar with little or no quartz.

Arkose

A type of feldspar-rich sandstone commonly derived from rapid disintegration of granitic rocks.

Asbestos

A commercial term applied to a group of silicate minerals that readily separate into thin, strong fibers that are flexible, heat-resistant, and chemically inert; also, a mineral of the asbestos group, principally chrysotile, anthophyllite, and crocidolite.

Ashlar

Prepared stone work of any type of stone.