Comminuted limestone

Surface layers may be calcium carbonate, hydroxide or, in freshly broken crystals, possibly calcium oxide. It is now well established that coccoliths in chalk are coated with very thin aluminosilicates (smectites and other clay minerals) and organic matter (humates, etc) [6]. During comminution, compaction or metamorphosis, these coatings may be disrupted or may still adhere to the calcite surface. Aluminium silicates have been identified in pure limestones and pure marbles, and have been shown to be unattached to calcite fragments. 

Carbonate sedimentary rocks are dominantly of marine origin. Many limestones are composed of fossilised shell debris in various states of comminution, some fine grained carbonates such as chalk (q.v.) may be entirely composed of sub-microscopic phytoplankton. Algal mats secrete aragonite particles and coral reefs are CeiCO structures which may be preserved, fossilised, intact or degraded to produce other limestones. As discussed above, allochems such as faecal pellets and ooliths may be... 

Comminution in stirred media mills (varying sizes and operational parameters), limestone, and graphene oxide platelets 0.8 0.37 Becker et al (2001) Halbig et al (2016)... 

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