Ardana is the fcitional planet in the "The Cloud Minders," episode of Star Trek: The Original Series (Episode 74, Season 3, 2-28-1969), A Star Trek Federation member world, it is widely known for its capital city of Stratos, an anti-gravity elevated metropolis. It was also known as the only known planet that mines zenite.
Native to the planet were a humanoid race, Ardanans, who were divided into two castes, a labor class of Troglytes and an intellectual ruling class of Stratos city-dwellers. The caste system was riven with conflict. Despite its membership in the Federation, Ardana employed torture and capital punishment. In 2269, the Enterprise came to obtain zenite for use to prevent a bacterial plague on Merak II.