Gem is a representative of a mute empathic race native to the Minara system which the Federation has only had one recorded encounter with. She was given the appellation Gem by Dr. McCoy on that occasion, as she had never had a spoken name before. Gem, along with McCoy, Captain Kirk, and Mr. Spock was held in a subterranean cavern by a race known as the Vians, who were assessing her people for their worthiness to be rescued and transplanted from Minara before the Minaran sun exploded. The Vians knew that the Minarans had a unique power to heal, but felt that only if they could learn self-sacrifice in the application of this power would they be worthy of survival. Through her exposure to the humans in extreme circumstances, the Vians hoped she would learn this, so they put the officers through torture to teach her. Ultimately, the three were faced with a choice as to which would suffer a potentially fatal procedure, and Gem witnessed each of them attempt to sacrifice himself for the others. She learned the trait, although she was prevented by McCoy when she attempted to demonstrate it. The Vians, however, agreed that her people had passed the test and used their advanced technology to heal her wounds and McCoy's.