The crystal brooches (also known as medallions, signet jewels and amulets) are a trio of items appearing in the AngieYaz/RoseOfSharon reboot of Sonic Underground. They are royal artifacts given to Sonic, Manic and Sonia when they were born, crafted by a royal jeweler, the great mage Wolfthorpe.
They appear to be made of a glass or clear/white crystal like material that resemble musical instruments and have the power to transform into its respective instrument (or put the triplets into their royal armor) when the wearer touches them, or waves their hand over them, in a blast of colored light. The power of these brooches can only be unlocked when the siblings and Amy Rose achieve harmony with one another and later were able to use their medallions' power freely.
When in instrument state, they can be used as traditional musical instruments, or can be used as powerful weapons in combat for self-defense; however, the use of the instruments, for either combat or music, costs power and after use the instruments will return into its medallion state to "recharge".
An important use for these artifacts in medallion state is their ability to free the mind of those that have been roboticized, this is done when the power of the medallions is directly forced to the Robian through a stream of energy that overcomes the mind control and frees the conscious; however, this process uses a lot of medallion energy and the effects are only temporary as after a certain period of time, the mind will be roboticized again (in the original show, it would last only for a few minutes, but in the reboot it's several hours).
The triplets' brooches can also be used to fire off a strong beam of energy to attack enemies. Sonic used his in The Big Melt to fight against Queen Sauna and ultimately defeat her, unfreezing Mobius from the eternal winter that she was about to cast upon it and destroying the crystals and comet she was using to do so.
Sonic on guitar
Sonic plays an electric multi-neck guitar. The body of the guitar being purple and yellow resembling Sonic's head. This is also the instrument seen in the Sonic Underground logo. The guitar is capable of shooting lasers from the headstocks, with the trigger of these lasers sometimes being a strum of the strings. Unlike the other two medallions the guitar has the least amount of danger.
As a medallion, it is carried with a red string and gives off a blue light when used.
Amy on bass guitar
Amy plays an electric multi-neck bass guitar. The body of the guitar being pink and red resembling Amy's head. The guitar, like Sonic's, is capable of shooting lasers from the headstocks, with the trigger of these lasers sometimes being a strum of the strings. Like Sonic's brooch, the guitar has the least amount of danger. It was crafted for Amy on Sonic's request (by the same royal jeweler, who was working for the Resistance at the time) and given to Amy as a gift by Sonic.
As a medallion, it is carried with a hot pink string and gives off a deep red light when used.
Manic on drums
Manic plays the drums; unlike traditional drums, they appear more like circular machines with yellow rims with only the cymbals being traditional. Manic can create and control quakes with his drums which is effective for leveling and demolition. He is also able to push and force earth and rocks skywards. He can even shoot lightning from the drumsticks. He is also shown using his drums to cause a tornado made of uncontrolled Chaos Energy to dispel. When under fire, the cymbals can be used as reflective shields to defend himself with. Manic's medallion is said in the series to be extremely dangerous if not used with caution due to its seismic powers. In the theme song, the drums fired a laser at a SWATBot as well and the same capabilities are used in the series.
As a brooch, it is carried with a blue string and gives off a green light when used.
Sonia on piano
Sonia plays an electric keyboard which comes with a stand for her to play, or as a weapon the keyboard can alternatively be a dual-handed laser gun. The laser point being at the side of the keyboard and has a gun trigger for laser fire. When being played as an instrument, a second laser can be shot from the back of the instrument when certain keys are pressed. Other than lasers, Sonia is able to summon mist when she plays a certain tune, granting her and her brothers cover for escape or confusion.
As a brooch, it is carried with a yellow string and gives off a pink light when used.
- In the reboot, Amy, Zak, Wheezie and Steve are the only new characters to receive medallions. Steve and Amy's instruments are a bass guitar and an accordion, respectively. The dragons' are simple musical notes that turn into a sword and a boomerang, respectively.