atomic number 20, Ca, calcium - a white metallic element that burns with a brilliant light; the fifth most abundant element in the earth's crust; an important component of most plants and animals

atomic number 9, fluorine, F - a nonmetallic univalent element belonging to the halogens; usually a yellow irritating toxic flammable gas; a powerful oxidizing agent; recovered from fluorite or cryolite or fluorapatite

mineral - solid homogeneous inorganic substances occurring in nature having a definite chemical composition