The Sky Spire is a spire constructed by Homeworld Gems, free floating in the air around the surrounding mountains with smaller floating rocks leading towards it. It is the former home of the Heaven Beetle, who lived in a tiny modern sized house on a little platform surrounded by water, at the top. A spiral light-grey hallway with orange half oval roof tiles travels around the structure to a dome area.
The Sky Spire is where the Heaven Beetle resides. Steven, Pearl, and Amethyst travel here to collect the beetle, succeeding only after a confrontation with a Big Bird. The Big Bird had swallowed the Heaven Beetle some time before the arrival of the three, and Steven retrieves it while in the Big Bird's stomach. Steven is rescued from the monster's belly by Opal. According to Bismuth the spires are where the most intelligent gems think.
Steven, Pearl, and Amethyst travel here to collect the Heaven Beetle at the top of the spire. Until being confronted by Big Bird, Opal comes to the rescue when Steven and Steven Jr. (a goat) get eaten by it while finding the Heaven Beetle is there too.
Schematics for the Sky Spire are later seen on Moon Base computer display.