Riga-Priam

Riga-Priam was a planet with plentiful quartz reserves. At some point, the Master travelled to Riga-Priam with the intent of looting it of its quartz, (PROSE: Missy on Trial) but found the planet taken over by the Monk. The Master tracked down the "lynchpin" of their psychic control over the people of Riga-Priam, who turned out to be a little girl. Without a second thought, the renegade then chucked the little girl into an active volcano, freeing Riga-Prima — and leaving the Master free to rob them — at the cost of the girl's life. (TV: The Lie of the Land)