Helium

Helium's applications utilize its cold, inert or buoyant properties. As a cooling agent, helium is used in basic scientific research, medical imaging (NMR) and various analytical or production processes. Helium is also used in welding and cutting applications and in lasers. Leak detection, deep sea diving and balloons also rely on helium's special properties.
Helium is another member of the group known as "rare" gases and has no color, odor or taste. Helium is the second lightest element, one-seventh as heavy as air. It is chemically inert, has low solubility in water and can not be made to burn or explode. Helium is the coldest known liquid at -452°F.
Helium is difficult to source. Most helium gas is extracted from natural gas sources containing from 1% to 7% by volume. These type of natural gas deposits are not common and mainly exist in certain areas of the United States, Canada, Australia, Qatar, Poland and Russia.