Clay—mica group

Examples are the mica group (e.g., KMg3(OF[)2Si3A10io) of which biotite, (K(Mg,Fe)3(OH)2Sl3A10io) (Figure 1.55) and talc (Mg3(OFl)2Si40io) are members, and contains a sandwich of two layers with octahedrally coordinated cations between the layers and clay minerals such as kaolin, Al4(OH)8Sl4C3io. 

Illite and pyrite were specifically cited in the above discussion to make a point relative to the precision and accuracy with which coal minerals can be quantified by XRD. First, illite is NOT a mineral. Illite is "...a general term for the clay mineral constituents of argillaceous sediments belonging to the mica group"... 

To our knowledge, only few studies were done on the determination of the surface heterogeneity of solids using IGC at finite concentration, if we exclude the works recently done in our group. In this instance, we first examine the case of solids that are heterogeneous on a quite macroscopic scale, originating generally from a lamellar structure like clays, micas or talcs. 

The clay minerals are distinguished by their size (<2-3 pm) and extremely active surface chemistry. A few clay minerals, such as micas, do occur in silt and larger sizes. The most common clay mineral groups are those of kaolinite, smectite, and illite. Kaolinitic minerals are characterized by a rigidly held, hydrogen-bonded, nonexpansive, double-layer... 

These minerals are hydrated aluminosilicates which are characterized by a sheetlike structure and can be conveniently divided into three groups (1) the kaolinite group, (2) the mont-morillonite group, and (3) the potash clay (or hydrous mica) group (Table 7.7). In the kaolinite group, all have the same chemical composition and differ only in individual crystal structures. The montmorillonite group can be represented by means of ion substitutions in the general chemical formula. For example, in montmorillonite itself, approximately 16% of the aluminum... 

Chlorite group Clay minerals group Cobalt group Feldspar group Metal pigments Mica group Aluminium Aluminium hydroxide,... 

Aluminium group Chlorite group Clay minerals group Feldspar group Mica group Sheet silicates group Silicates group ... 

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