Most minerals are composed of two or more elements with their atoms arranged in a regular structure, called a crystal lattice or crystal structure. In chemistry, this is known as a compound. To visualize crystal structure, think of balls attached to other balls with sticks to make regular three-dimensional patterns. The balls represent atoms and the sticks represent the forces between the atoms. Electromagnetic forces between atoms hold some chemical compounds together. In other compounds, the atoms form covalent bonds, which means they share electrons. Scientists classify many minerals into groups based on the types of atoms found in the minerals. For example, oxides consist of metallic atoms bound to oxygen atoms, and sulfides are combinations of metal and sulfur atoms.

Certain rare elements such as beryllium, tantalum, lithium, and yttrium occur in small quantities scattered around the world, rather than in rich mineral veins that are easy to mine. The economic importance of these elements, however, has grown substantially over the past few decades, as scientists and engineers have found new ways to use them. For example, tantalum, found primarily in the mineral tantalite, helps miniaturize the electronic components inside computers, gaming consoles, and cell phones. Lithium powers those portable devices by making batteries last longer. Beryllium, found in more than 100 minerals, goes into lightweight structural components of fighter jets, guided missiles, and spacecraft. When added to diesel fuel, cerium lowers the noxious emissions from trucks. Gallium and indium, two elements that are considered electrical semiconductors, go into light-emitting diodes (LEDs). Yttrium is a key ingredient in medical lasers.

For example, the mineral bastnasite (or bastnaesite), which contains cerium, lanthanum, and yttrium, was discovered in Sweden and occurs. The economic importance of these elements, however, has grown substantially over the past few decades, as scientists have put them into many high-tech devices. Cerium added to diesel fuel helps trucks run with fewer noxious emissions; scandium, alloyed with aluminum and other metals, makes lightweight lacrosse sticks and components for fighter jets; yttrium is a key ingredient in medical lasers.