What are the uses of laterite rock


Author: Torsten Purle (steine-und-minerale.de) | Last update: 01/19/2021

Laterite - properties, formation and use

English: laterite | French: laterite

Laterite = ocher-colored brick

The first mention of laterite is thanks to the Scottish physicist Francis Buchanan-Hamilton (1762 to 1829). Under the paragraph "Laterite" in 1807 in his work "A Journey from Madras through the Countries of Mysore, Canara and Malabar" he describes the occurrence, properties and use of the rock in India.
In this context, Buchanan-Hamilton emphasizes the use as a building material ("one of the most valuable materials for buildings"), the ocher tone due to the iron content ("very large of iron in the form of red and yellow ochres") and the resistance to wind and weather ("resists the air and water").
Since the brick-red color reminded him of bricks, he named the stone after the Latin word later for brick Laterite; whereas in India the rock is known as "Shuri cull or itch stone".

Properties of laterite

definition: Laterite is a sedimentary rock that results from the weathering of various rocks in tropical and subtropical climates.

Laterite is red, reddish brown to brown or black in color, the darkening of the rock increasing with age. The reason for the color intensification is the oxidation of the minerals it contains.

The mineral composition of laterite is characterized by kaolin, quartz, limonite, rutile, hematite, gibbsite, goethite, lepidocrocite and anatase.
However, the mineral inventory varies with location and parent rock; However, various iron and aluminum oxides are always represented.

The structure of laterite is massive, but can also be porous or pisolithic. The distinctive characteristic of pisolithic (pea-shaped) small spheres - mostly made of grape goethite (so-called glass head), around which the other minerals are deposited or fill the gaps.

Formation and distribution of laterites

Laterite emerges as sedimentary rock through the decomposition of other rocks and subsequent solidification of the loose material.
The parent rocks of laterite are, for example, dunite, peridotite and serpentinite, which weathered under warm and humid climatic conditions. In this case, it is chemical weathering that comes into play and ensures that numerous elements (e.g. Mg, Ca, Na) are washed out.
Instead, there is an accumulation of poorly soluble iron and aluminum or new formation of iron and aluminum-containing minerals such as goethite, hematite or gibbsite.

Significant laterite deposits exist in France, Greece, Turkey, the Congo, Ethiopia, India, Indonesia, Malaysia, Australia, Brazil and the USA, among others.

Importance and use of laterite

Laterite has always been used as a building material. In doing so, laterite is used, which is older. With increasing age, laterite becomes harder and is suitable as building block and brick. Laterite is also partially mined in order to benefit from the ore content of the rock.

See also:
⇒ Weathering of rocks
⇒ The formation of sedimentary rocks
⇒ Characteristics of rocks: main and secondary parts

⇒ Buchanan-Hamilton, F. (1807): A Journey from Madras through the Countries of Mysore, Canara and Malabar. Volume 2
⇒ Maresch, W., Medenbach, O .; Trochim, H.-D. (1987): The colored natural guide rocks. Mosaik Verlag GmbH Munich
⇒ Murawski, H. (1992): Geological Dictionary. Ferdinand Enke Verlag Stuttgart
⇒ Okrusch, M. and S. Matthes (2009): Mineralogy: An introduction to special mineralogy, petrology and deposit science. Springer Verlag Berlin Heidelberg