Talk:Gems/@comment-4352233-20140220190544

According to a TVTropes WMG, gems are used for powering machines. Different colours produce different elemental energy sources. Rubies give heat, sapphires make water power, emeralds for wind powered machines, and topaz is for basic electrical power. These, along with magic, are very eco-friendly sources of energy, because the ponies are eco-friendly themselves.