The Jersey Quarry is a mining location on Earth visited a few times by the Crystal Gems.
History[]
Season 3[]
After finding reports of miners disappearing or being driven out by an "Unknown Presence", the Crystal Gems and Mane Six venture into the location in order to figure out what the issue even was. Upon arrival though, they run into Time Jumper, who not only poofs all of the Gems (except for Amethyst), but also seemingly teleports the Mane Six away. Amethyst returns there numerous times in different timelines, each time being bested by Time Jumper, until she finally gives up and gets poofed herself in the same location.
My Little Universe II[]
The Harmony Gems return to the Quarry on a monster hunting mission.