Mineralogical Crystallography: X. Carbonates

The minerals belonging to the class of carbonates constitute 18% of the Earth’s sedimentary shell, which is 1.7 wt % of the Earth’s crust mass. Carbonates are the main minerals of marine sediments. This is a widespread but crystallochemically understudied class of minerals, which includes 290 species. Among the 90 anhydrous carbonates, two large groups are distinguished, which include minerals with rhombohedral and orthorhombic symmetries, accumulating 90% of carbon of the Earth’s crust. The characteristic structural features of the main representatives of these groups and other common carbonates are considered. Data on possible transformations of carbonates in deep geospheres are reported.