Sapphire is a member of the Crystal Gems who made her official debut in "Jail Break". Previously a member of Blue Diamond's court, her mission was to inform her Diamond about the Rebels' attack using her future vision. Over 5,750 years ago, Sapphire lived on Homeworld, as an aristocratic Gem and part of Blue Diamond's court. She was part of the diplomatic team sent to stop Rose's Rebellion on Earth, along with 3 Rubies assigned to guard her. Sapphire isn't just upset because Rose lied to her. She's upset because of what that means for her future vision. This is something that I've been thinking of since we saw Sapphire run off, and not Ruby.