Individual talc grains have a grain

Individual talc grains have a grain width diameter of 6–14 µm and an average thickness of less than 0.5 µm in all samples (Figures 4c–4f).
Thus, Emirdağ talc
may be classified as microcrystalline talc due to its
relatively low basal/edge surface ratio. According to the
literature, platy talc can be classified as microcrystalline
or macrocrystalline (Ciullo & Robinson 2003; Ferrage et
al. 2003). Microcrystalline varieties are naturally small in
plate size and comprise compact, dense mineral particles.
Macrocrystalline varieties contain relatively large plates
with higher aspect ratio (high basal/edge surface ratio).
The grinding of microcrystalline talc is easier than that of
macrocrystalline talc (Ferrage et al. 2003). The morphology
(e.g., basal/edge surface ratios, degree of delamination)
of talc particles as layered clay minerals plays a decisive
role in its usability as a filler material, especially in plastic,
coating, and paint industries (Yuan & Murray 1997;
Ciullo & Robinson 2003; Ferrage et al. 2003) and also
on its wettability and flotation behavior (Hiçyilmaz et al.
2004). For example, kaolin used in paper sludge and the
spherical halloysite (both kaolinite and halloysite have
1:1 types of layer structures; halloysite usually contains
some interlayer water) showed the lowest viscosity,
followed by platy kaolinite and tabular halloysite (Yuan &
Murray 1997). This indicates that the morphology of filler
particles directly affects the rheological behavior of their
suspension and, in turn, their usability. The morphology
of talc particles is dependent on different factors, such as
geological formation conditions of talc deposits (Ciullo
& Robinson 2003; Nkoumbou et al. 2008b), particle size,
grinding method, and conditions (Sanchez-Soto et al.
1997; Ferrage et al. 2003; Hicyilmaz et al. 2004; Ulusoy
2008).