Scanning electron microscopes are used for imaging small specimens at magnifications from 100 to 100,000 times their actual size. They do this by collecting emitted electrons, rather than collecting light like traditional optical microscopes. The instruments permit scientists and engineers to view tiny objects or features very closely, thereby allowing biologists to see an organism's protective coating, metallurgists to inspect corrosion of metals, or geologists to quantify mineral abundances, study mineral assemblages and quantify mineral associations.