Lithium 101
Lithium is the first element in group 1 (alkali metals) of the periodic table. In solid form it is half as dense as water and lithium metal is the least dense metal. Its chemistry is dominated by its tendency to lose an electron to form Li+. Due to its highly dispersed occurrence in the earths crust, Lithium is considered rare,
Economic concentrations of Lithium occur in salts from brines and in the minerals petalite, spodumene, amblygonite-montebrasite and lepidolite in large pegmatite deposits.
Lithium is mixed (alloyed) with aluminum and magnesium for light-weight alloys, and is also used in batteries, some greases, some glasses, and in pharmaceuticals.
The WebElements: periodic table on the web has an excellent overview of lithium and its properties. Some of the more informative links are:
http://periodic.lanl.gov/elements/3.html