Ragna Rock

Ragna Rock is a location that appears in Sonic Boom: Fire & Ice. It is described as a mythical island on earth where a rare element called Ragnium can be found.

Sonic Boom: Fire & Ice
When Ragna Rock was discovered by Dr. Eggman, the doctor began mining it for its resources of the supercharged Ragnium element to power his robots while piping off the messy by-products from the operations to the adjacent islands, creating fissures that damaged the environment. Sonic would eventually arrive on Ragna Rock where he would have to save Eggman from his own creation, D-Fekt.

Trivia

 * The island's name is a play on the word "Ragnarok", a series of future events in Norse mythology that foretells the destruction of the gods and of all things in a final battle with the evil powers.