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(Minerals) a clay mineral of the mica group, found in shales and mudstones. Crystal structure: monoclinic. Formula: K1–1.5Al4(Si6.5–7Al1–1.5O20)(OH)4
[C20: named after Illinois, where it was first found]


(ˈɪl aɪt)

any of a group of clay minerals, hydrous potassium aluminosilicates, characterized by a three-layer micalike structure and a gray, light green, or yellowish brown color.
[1937; Ill(inois) + -ite1]
il•lit•ic (ɪˈlɪt ɪk) adj.
References in periodicals archive ?
The most prevalent Estonian clay minerals are: illite, illite-smectite, kaolinite, and chlorite.
Illite content decreases, while chlorite content increases with depth, contributing over 30% of the clay fraction.
2013a) SA-11-12A Schmidt et Silcrete outcrops with trace Illite, Western al.
The soil was rich in illite and vermiculite clay minerals with high cation exchange capacity (CEC) with major part of applied K as fixed making it immediately unavailable to the plants.
X-Ray Diffraction technique reveals chlorite to Illite clay minerals with major constituent as quartz.
It is also found in this investigation that kaolinite, illite, chlorite, mixed layer of smectite and illite are abundant in Jincheng Mining area.
1]) to investigate Mg dispersion for pure montmorillonite, kaolinite and illite clays.
Whereas phosphatic rocks are feedstock for both conventional and unconventional phosphate fertilizers, potassium silicates, such as feldspars, biotite, phlogopite, and muscovite, and rocks with feldspathoids, such as leucite, nepheline and clayrich sediments, especially illite, are the basis for alternative potassium fertilization (Straaten, 2010).
The quantities of smectite rich illite/smectite mixed layers were calculated using the mineral factor of smectite, while the percentages illite/smectite mixed-layer rich in illite were determined using a factor based on the intensities ratio of the reflections situated at 4.
The main crystalline components of the coal gangue could be identified in Figure 2 as illite ([X.
Clay minerals in facing water are active (absorbing water and swelling potential) and inactive, Shales often have inactive Clay minerals such as Kaolinite, Illite and active minerals such as Montmorilonite.
The mineralogical composition of the sample is dominated by calcite, quartz and illite.