Crystal Lock

The Crystal Lock is a special type of gimmick that appears in Sonic Boom: Rise of Lyric. It is an lock mechanism created by the Ancients which uses the Chaos Crystals to open large paths. In gameplay, unlocking these locks grants access to new areas.

Description
The Crystal Locks are fairly large dome-shaped stone figure with golden metallic outlines. On their front they have a raised cylinder with a glowing recess shaped like one of the Chaos Crystals (the Sky Crystal is not included). There are a total of seven Crystal Locks, each with a recess matching one of seven Chaos Crystals, and they are found in the hub world areas of Cliff's Excavation Site and on Bygone Island in the game.

The purpose of the Crystal Locks is to unlock large paths that block the player's access to the different areas in the game or sections of their respective hub worlds containing the access points to said areas. Most of these paths are unlocked by opening large gates while one is open by raising a large bridge, another by activating a teleportation hub and a third by activating an elevator.

Unlocking the Crystal Locks allows the player to move onto the next area; essentially, they allow the player to get to the next level when needed and not before. Placing the matching Chaos Crystal in the recess on a Crystal Lock will open the path and the Crystal Locks themselves will slide into the ground.

To unlock a Crystal Lock in gameplay, the player has to have obtained its matching Chaos Crystal and then approach it. The path will then open automatically.

History
The Crystal Locks were created by the Ancients about a thousand years ago to barge any way to most of the Chaos Crystals and designed them so only said Crystals could unlock them. Over time though, the knowledge surrounding the Crystal Locks were forgotten by all, and the only thing history buffs like Amy Rose could deduce from them that they were meant to hold something powerful.

A millennia later, Team Sonic began hunting down the Crystal Locks to find the Chaos Crystals before Lyric. Thanks to Cliff's help, the team was able to find the first lock which led to them to a map that showed the location of the rest. Over the next day, Team Sonic managed to unlock all the Crystal Locks and find the Chaos Crystals, only to have them taken Lyric.

Trivia

 * Despite that the Chaos Locks are meant to block travelers' paths to the Chaos Crystals, several people have settled down beyond these blocked paths. This include Salty on beyond the Sun Crystal's gate and the farmlanders and the turtle village beyond the Radiant Crystal's gate.