Timeshift Stone

Timeshift Stones are bluish-purple stones in Skyward Sword. They are inscribed with a glowing emblem that resembles the Sheikah Symbol.

Location and Uses
The stones, which were excavated and refined in the Lanayru Mining Facility, are found in the Lanayru Desert region. They are magical objects that can manipulate time when struck. Link can strike the Timeshift Stone to awaken and replenish the land, technology, and its robotic citizens as to how they once were before the carelessness of people of the region caused for the land to wither from its quick depletion of natural resources. Fi determines that Timeshift Stones were once used as a source of power for the Lanayru Province. Unrefined Timeshift Stones can be found within mine carts in the Lanayru Mining Facility, which can be struck to activate a small field surrounding the cart, activating and mobilizing the cart in the process.

Remains of enemies that are near a Timeshift Stone will come back to life when they are activated and enemies such as the Ampilus will revert to an infant state. In the past state, electrical barriers may appear, blocking Link's path, whereas spiky, metallic barriers in the present disappear. Additionally, there are fans that serve as barriers within the past, blocking Eye Switches. The past state is also the only time when Ancient Flowers may be found.

While in search for Lanayru's part of the Song of the Hero, the Ancient Robots in Lanayru Gorge tell Link that Lanayru oversees the Timeshift Stone mining project.

Timeshift Orbs
Portable Timeshift Stones called Timeshift Orbs appear within the Pirate Stronghold and Sky Keep. They serve a similar function to the normal variant, but instead can be carried and remain constantly active.

Certain areas contain raisings in the earth that appear in the past, which can serve as platforms or roadblocks.

If Link installs the Timeshift Orb in the Pirate's Stronghold in the pedestal near the entrance, the "mouth" outside will raise, allowing Fi to receive data and dowse for Skipper's Ship. Link must use the Timeshift Orb within Sky Keep to activate conveyor belts in order to move it to separate sections of the same room.

Theory
The Gate of Time is made of a blueish-purple material that is a dark purple when not activated, and warps time. All three of these qualities fit something made of Timeshift Stones. Therefore there is a high probability, also considering the handiwork of the circuits in the Gate, that the Gate of Time is made of Timeshift Stones. If this were true, it would explain why the Ancient Robots are mining so many Timeshift Stones: to make the Gate of Time.

Trivia

 * If enemies from the present come into the field of an active Timeshift Stone, they will disappear. They will reappear at the place they vanished at if the Timeshift Stone is later deactivated.
 * Hyrule Historia hints that the Ocarina of Time may be made from Timeshift Stones.