What is "lithology"

Lithology \Li*thol"o*gy\, n. [Litho- + -logy: cf. F. lithologie.]

1. The science which treats of rocks, as regards their mineral constitution and classification, and their mode of occurrence in nature.

2. (Med.) A treatise on stones found in the body.

study of rock-formation, 1716, from Modern Latin lithologia, from litho- + -logia (see -logy).

n. 1 The study of rocks, with particular emphasis on their description and classification. 2 The general composition of a rock or rock sequence.

The lithology of a rock unit is a description of its physical characteristics visible at outcrop, in hand or core samples or with low magnification microscopy, such as colour, texture, grain size, or composition. It may be either a detailed description of these characteristics or be a summary of the gross physical character of a rock. It is the basis of subdividing rock sequences into individual lithostratigraphic units for the purposes of mapping and correlation between areas. In certain applications, such as site investigations, lithology is described using a standard terminology such as in the European geotechnical standard Eurocode 7.