The alicorn amulet is a gray triangle with a rhombus-shaped ruby. Above said ruby lies a pair of red-and-dark gray wings, long with a unicorn head (in profile view) with red eyes.
The alicorn amulet gives it's user great power, such as the ability to perform age spells. However, the user's eyes and magical aura turn red, and the user is corrupted.
The alicorn amulet's history before the episode is unkown, aside from the fact that it lies in a shop. The storekeeper claims that the amulet is not for sale, but ends up selling it anyway. The buyer turns out to be Trixie.