Morganite is the pink variety of beryl, the "mother of gemstones". While there are other pink gemstones (rose quartz and tourmaline come to mind), morganite is the most durable and rarest. It is quite unusual to find morganite jewelry, making those quite valuable.
Other gemstone color varieties that belong to beryl include emerald, heliodor, and aquamarine. Other colors of beryl are simply referred to by their color, such as red beryl.
Morganite is colored by trace amounts of manganese that find their way into the crystal structure. It is named after J.P. Morgan, a famous American industrialist. Morganite is found in China, Brazil, Madagascar, and California, Maine, Connecticut, and North Carolina in the U.S.