Foliated carbons

Figure 8.14 Cross-sectional view of vapor grown carbon fiber showing the foliated structure (courtesy of G. Tibbetts).

Relatively pure carbonate rocks when subjected to regional metamorphism simply recrystallize to form either calcite or dolomite marble with a granoblastic texture. Any silica present in a limestone tends to reform as quartz. The presence of micas in these rocks tends to give them a schistose appearance, schistose marbles or calc-schists being developed. Where mica is abundant, it forms lenses or continuous layers, giving the rock a foliated structure. 

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