Demarco Castle

Demarco Lamonte Castle (born June 20, 1981), also known as Gemstones, is an American singer and rapper from Chicago. He is most well known for his affiliation with fellow Chicago artist Lupe Fiasco. Formerly under the stage name Gemini, Castle began his hip hop career through Lupe Fiasco's Atlantic Records imprint, 1st and 15th Entertainment, where he was set to release his debut album, Troubles of the World, in early 2009. The album has since been delayed indefinitely due to his departure from mainstream hip hop and the discontinuation of 1st and 15th Entertainment.