Beryllium has several roles in industry, including use as an X-ray window, a moderator in nuclear reactors, a part of several alloys and a component in ceramics. It is very light and has a relatively high melting point in its metallic form. Beryllium and its compounds are highly toxic to humans, despite having a sweet taste that earned it its original name, glucinium.
Beryllium is not found as a pure metal in nature, instead generally being part of relatively complex minerals such as its namesake, beryl. Emeralds are actually just a pure type of beryl, as was first realized by Abbe Hauy in 1798. Later that same year, Louis-Nicolas Vauquelin discovered that an unknown element, beryl, was present in these minerals. Beryllium was not isolated until 1828.
Beryllium is relatively transparent to X-rays and is used to make windows for X-ray tubes. It emits neutrons when irradiated and is used as a neutron source in many applications. Beryllium bronze, which is only 2 percent beryllium and 98 percent copper, is very wear-resistant. It is alloyed with nickel to make springs and non-sparking tools. Beryllium oxides have high strength, hardness and corrosion resistance, while acting as an excellent heat conductor and decent electrical insulator.