Soil Genesis and Development, Lesson 1 - Rocks, Minerals, and Soils Glossary

Having a pH lower than 7, having a higher concentration of H+ ions.

Not equal in all directions; having a preferred or dominant direction.

A cation which does not contribute to soil acidity, principally Ca²⁺, Mg²⁺, Na⁺, or K⁺.

materials or substances which glue particles together

A soil inorganic particle smaller than 2 micrometers (< 0.002 mm.) diameter in the USDA classification system. Clay is also a textural class name for a soil having at least 40% clay-sized particles.

molten rock expelled from the earth during a volcanic eruption.

molten rock located deep beneath the surface of the earth

pool or collection of molten rock or magma beneath the surface of the earth

rock liquified by temperature and pressure

an extrusive igneous rock that formed without sufficient time for crystal formation

bedrock exposed at the surface of the earth

A soil inorganic particle in the range of 50 to 2000 μm (.05 to 2.0 mm) diameter in the USDA classification system. Sand is also a textural class name for a soil having at least 85% sand-sized particles.

A soil inorganic particle in the range of 2 to 50 micrometers (or 0.002 to 0.05 mm) diameter in the USDA classification system. Silt is also a textural class name for a soil having at least 80% silt-sized particles.

Sedimentary rock made up or composed of silt size particles.

chemical reaction which proceeds without a solvent (i.e.,  water)

The complex combination of physical, chemical and biological processes that decompose, disintegrate and alter rocks and minerals at or near the Earth's surface. Weathering can be subdivided into chemical weathering, physical weathering, and biological weathering.  (Soil and Environmental Science Dictionary)