👉 Klockmannite is a mineral that is commonly found in the Earth's crust. It is composed of silicon dioxide (SiO2) and calcium carbonate (CaCO3), and it has been named after German physicist Walter Klockmann, who first isolated it in 1907. The structure of klockmannite is similar to other minerals like calcite or ilmenite, but the chemical composition differs. It is a greenish-white color with a hardness of about
