Aggregate (geology)

For other uses, see Aggregate (disambiguation).

In the Earth sciences, aggregate has three possible meanings.

Crystal aggregate (lapis lazuli from Afghanistan)

Construction aggregate (a gravel pit in Germany)

Soil aggregate in Spain

In mineralogy and petrology, an aggregate is a mass of mineral crystals, mineraloid particles or rock particles.^[1][2] Examples are dolomite, which is an aggregate of crystals of the mineral dolomite,^[3] and rock gypsum, an aggregate of crystals of the mineral gypsum.^[4] Lapis lazuli is a type of rock composed of an aggregate of crystals of many minerals including lazurite, pyrite, phlogopite, calcite, potassium feldspar, wollastonite and some sodalite group minerals.^[5]

In the construction industry, an aggregate (often referred to as a construction aggregate) is sand, gravel or crushed rock that has been mined or quarried for use as a building material.

In pedology, an aggregate is a mass of soil particles. If the aggregate has formed naturally, it can be called a ped; if formed artificially, it can be called a clod.^[6]

Construction aggregate examples

• basalt

• dolomite
• granite
• gravel
• limestone^[7][8]
• sand
• sandstone

Use in industry

Aggregates are used extensively in the construction industry^[9][10] Often in making concrete, a construction aggregate is used,^[4] with about 6 billion tons of concrete produced per year.^[11]

See also

• Interfacial Transition Zone (ITZ)
• Soil structure