Ragnium

Ragnium is a substance that appears in Sonic Boom: Fire & Ice. It is a rare mineral which is highly suitable as robot fuel. It was discovered and harnessed by Dr. Eggman for a revenge scheme against Sonic.

Description
Ragnium is a supercharged element that resembles green crystals. A naturally-occurring substance, the only known deposits of it are found underground on the island of Ragna Rock. When melted down and combusted, it can be used as a powerful fuel source for robots, granting them increased speed and agility.

Ragnium and its waste products appear to create potent energies with elemental affinities known as Fire and Ice energy. These energies can be harnessed by both robots and organic creatures to trigger Fire Mode and Ice Mode, abilities that lets the users superheat or freeze objects in an instant. Additionally, Ragnium emits a traceable radiation.

Sonic Boom: Fire & Ice
Discovered by Dr. Eggman, the doctor would mine Ragnium from Ragna Rock as a fuel for his EggBot Racers for a plan to discredit his rival Sonic; if his Ragnium-fueled robots could allegedly outrun Sonic, the hedgehog's reputation as the fastest thing alive would be ruined. Meanwhile, Eggman would pipe off the by-products of his operation to adjacent islands, creating Ragnium-infused fissures that damaged the environment. To mine Ragnium, Eggman created the robot D-Fekt, although it did not live up to its intended purpose.

During Team Sonic's climatic battle with D-Fekt on Ragna Rock, D-Fekt ruined Eggman's Ragnium mine when building himself up, making it impossible to mine for Ragnium on Ragna Rock again.

Gameplay
In gameplay, Ragnium serves as a collectible that can be gained in various ways. Defeating a lesser enemy awards one Ragnium shard, while completing a Dragon Ring challenge in adventure levels give ten shards. Ragnium can also be earned via StreetPass, or by completing a level within a time limit or with a certain amount of Rings. Being defeated during a level makes the player loose the Ragnium they hold however.

After being collected, Ragnium can be traded with Tails at the Bot Racer Workshop in exchange for new content. It can also be used to unlock exclusive pieces of concept art in Sonic's Shack.

Trivia

 * If the order of hammers unlocked in Amy's House in Sonic Boom: Fire & Ice are implied to be indicators, then Ragnium is more elusive than the likes of bronze, silver, gold, platinum and titanium.
 * Ragnium is similar to Ragnite from another SEGA franchise, Valkyria. Along with having similar sounding names, both are minerals that are dug up and used to fuel machinery.