Kaolin booklets

Both D1 and D2 dolomite/ankerite types show evidence of partial dissolution, which preferentially affects the Fe-rich zones (Fig. 11B). Some intracrystalline dissolution pores contain authigenic kaolin-ite booklets. In some samples of the middle domain partially dissolved poikilotopic crystals of D1 and D2 are covered, and thus postdated, by thin chlorite rims (Fig. 11C). 

Hydrous kaolins are naturally occurring minerals found as hexagonal plates of varying crystalline uniformity. The plates are often associated with one another as stacks or booklets (Fig. 6.1). These particles have low aspect ratios and typically exhibit small surface area. Aspect ratio is defined by the ratio of the plate diameter to the plate thickness. 

Kaolin is the common name used for kaolinite (. v.), a white clay mineral of composition Al4[Si40io](OH)g derived from the weathering of feldspars. Correctly, kaolin consists of both crystalline and amorphous material, whereas kaolinite is completely crystalline. Particle size is normally extremely fine, though typically it appears as a highly laminated agglomerate of platelets (one author graphically describes it as a booklet ). Calcium, magnesium and potassium are also commonly associated with kaohn as trace elements. 

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