CaMgFeCO3

CaMgFeCO3 is a ternary carbonate mineral. It represents a solid solution series between the end-members dolomite (CaMg(CO3)2) and an iron-bearing analog where iron substitutes for magnesium. The chemical formula indicates the presence of calcium (Ca), magnesium (Mg), iron (Fe), and carbonate (CO3) groups. The exact proportion of iron within the structure can vary, leading to a range of compositions. Minerals in this series are typically found in metamorphic rocks, particularly those derived from carbonate-rich protoliths subjected to metamorphism. They can also occur in some hydrothermal vein systems. The presence and amount of iron influence the mineral's physical properties, such as its color, which can range from pale to dark brown or even black depending on the iron content. CaMgFeCO3 crystallizes in the trigonal crystal system, similar to dolomite. Its structure is characterized by alternating layers of calcium and (magnesium, iron) carbonate units. Identification and characterization often involve optical microscopy, X-ray diffraction, and electron microprobe analysis to determine the precise chemical composition. This mineral group is important for understanding the geochemical processes occurring during metamorphism and hydrothermal alteration of carbonate rocks.