Calcietgroep

Calcietgroep refers to a group of carbonate minerals that share a similar crystal structure and chemical composition based on calcium carbonate. The most common and defining member of this group is calcite itself, which has the chemical formula CaCO3. Calcite crystallizes in the trigonal crystal system and is known for its perfect rhombohedral cleavage, meaning it breaks along specific planes to form rhomb-shaped fragments. It is a very widespread mineral found in a vast array of geological environments, including sedimentary rocks like limestone and marble, as well as in hydrothermal veins and caves.

Other important minerals within the calcietgroep include aragonite and vaterite. Aragonite, also with the formula CaCO3, is a dimorph of calcite, meaning it has the same chemical composition but a different crystal structure, crystallizing in the orthorhombic system. While less stable than calcite at surface conditions, aragonite is commonly found in the shells of mollusks and corals, and also forms in certain geological settings. Vaterite is another polymorph of calcium carbonate, less common and even less stable than aragonite.

Minerals in the calcietgroep are characterized by their hardness, typically around 3 on the Mohs scale, and their reaction with dilute acids, where they effervesce vigorously, releasing carbon dioxide. This property is a key diagnostic feature for identifying calcite and related minerals. The calcietgroep plays a significant role in Earth's geology, forming sedimentary rocks that are crucial for understanding past environments and contributing to the formation of economically important resources like limestone used in construction and agriculture.