Gem is short for: the cut rock or even mineral, the gemstone an engine processed by Rolls-Royce plc, the Gem, primarily for use in the AugustaWestland Lynx helicopter. GEM was a GUI operating formulas developed by Digital Research in the early 1980's long prior to Microsoft Windows 3.1

Jem (which sounds such as gem) can be: the television animated series which aired in the mid-1980s, see Jem (animated) a musician Jemma (Jem) Griffiths: look at Jem (singer). the character around Harper Lee's To Kill a Mockingbird a 1980 book by Frederik Pohl, see Jem (book). an Ibanez electric guitar designed by musician Steve Vai