Quartz
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.
Inorganic residues of bilogical origin
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.
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.