Ancient Statues are minable statues found in the Ruins. They will drop a Gem and potentially 1 or 2 Thulecite. The color of gem that drops will be the same type that appears on the statue, either in the staff or at the base. If the statue does not have a gem embedded in it, it will drop Nightmare Fuel in its place.
The Ruins are the last remnants of a forgotten civilization located on a level below Caves. They are generated as a new world upon entering them, just like caves. Ruins have their own theme, terrain, and biomes. Various unique creatures, plants, and other objects reside within.

The appearance of the statues changes depending on the current state of the Ruin's Nightmare Cycle. In any state besides calm, they produce light. At the most intense state, the statues will be covered in Nightmare Fuel and gain a hazy glowing quality (though their light radius does not increase). If mined during the Nightmare, there is a chance for a Nightmarebeak or Crawling Nightmare to spawn.

The color (or presence) of the gem in the statues changes with each Nightmare Cycle or simply when reloading the game. This makes it possible to choose which gems the statues will drop after being mined.

The Mage statue, if examined closely, reveals it to be a lobster-like creature. This may suggest that the creatures who build them were related to Rock Lobsters.