They are the simplest fabric units in the soil, for example, sand grains, clay particles, plant fragments, etc.

They can have a mineral or an organic origin.

They form the groundmass of the soils or they are reorganised in the pedofeatures.

Mineral components

Coarse mineral components

Rocks fragments

Inorganic residues of bilogical origin


Fine mineral componentes


Organic components



Mineral components

They are defined depending on their size: coarse and fine materials. The limit between them is arbitrary, depending on the characteristics of every sample, the limit is between 10 and 2 microns.


Coarse mineral components

They are the recognisable and generally identifiable components in a petrographic microscope and they are individual grains.

There is a description of their: nature, level of alteration, shape, size, abundance, origin (inherited or new formation), etc.

The determination is carried out according to the different mineralogy handbooks. On this Web server there are several programmes dedicated to this subject.

In "OptMine" (multimedia programmes) there is an analysis of how the optic properties are used in the petrographic microscope to identify the mineral.

In "Arenas finas" (Fine Sands, Photograph Atlas) a wide range of minerals from this grain size fraction are shown.

In "Interest of the mineralogical study of coarse sands in soils" there is an analysis of the most frequent minerals in coarse sands of the soil and their possible origins and alterations are stated.






Fe compounds


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