atomic number 49, indium, In - a rare soft silvery metallic element; occurs in small quantities in sphalerite

atomic number 81, thallium, Tl - a soft gray malleable metallic element that resembles tin but discolors on exposure to air; it is highly toxic and is used in rodent and insect poisons; occurs in zinc blende and some iron ores

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