Calcite is widely distributed in nature.
In shallow seas or lakes, it often deposits to form extensive limestone layers.
Groundwater can dissolve limestone and also reform calcite, such as in stalactites, stalagmites, and travertine. Groundwater active in soil near the water table often forms calcite nodules distributed along a certain horizontal plane; geologists commonly refer to these as calcareous nodules.
Hydrothermal activity often forms calcite veins, some containing minerals and some not. Well-formed crystals are often found in geodes.
In carbonates formed by magmatic activity, calcite typically accounts for about 80%.
Furthermore, calcite also acts as a cement in clastic sedimentary rocks and as a mineral derived from the alteration of basic igneous rocks, contributing to various rocks. Due to groundwater activity, calcite veins frequently fill the fissures of various rocks.
Limestone formed by sedimentation often undergoes regional or contact metamorphism, during which the calcite within it recrystallizes to form coarser calcite aggregates-marble.
