Calamine the World Health Organization's List of Essential Medicines for being one of the most effective and safe medicines needed in a health system. Calamine is available over the counter as a generic medication. The wholesale cost in the developing world is about US$0.25–3.85 per 100-ml bottle. In the United Kingdom, it costs the National Health Service about £0.44. Calamine is used to treat itchiness. This includes from sunburn, insect bite, or other mild skin conditions. Calamine is mixed with either zinc oxide (ZnO) with about 0.5% ferric oxide (FeO) or a zinc carbonate compound. Calamine lotion is a component of
Period 6 element in 1839 as an impurity in cerium nitrate – hence the name "lanthanum", from the Ancient Greek "λανθάνειν" ("lanthanein"), meaning "to lie hidden". Although it is classified as a rare earth element, lanthanum is the 28th most abundant element in the Earth's crust, almost three times as abundant as lead. In minerals such as monazite and bastnäsite, lanthanum composes about a quarter of the lanthanide content. It is extracted from those minerals by a process of such complexity that pure lanthanum metal was not isolated until 1923. Lanthanum compounds have numerous applications as catalysts, additives in glass, carbon arc lamps