The fake Emerald is an object that appears in Sonic Adventure 2. It is an Emerald meant to bear similarity to a real Chaos Emerald, but it does not possess the same amount of power, and was designed to sabotage machinery.
The fake Emerald is an exact replica of the yellow Chaos Emerald. Because of this, it is a large, diamond-cut Emerald with a yellow hue, being of the same size and structure that a Chaos Emerald has. Its wavelength and properties are also identical to that of a real Chaos Emerald, enough that not even machines could tell the difference, meaning that the only way to tell the difference between the two is prior knowledge of which one is real and which is not. Also, one of the major differences between the real Chaos Emeralds is that it is designed to first reverse the energy field inside the real Chaos Emeralds and then explode. In the Japanese version, however, it is designed to absorb the energy of the Chaos Emeralds and explode.
The fake Emerald is less powerful than the real Chaos Emerald, although it still has Chaos Emerald energy. Sonic the Hedgehog was capable of using the Emerald to execute Chaos Control. This does not appear to be a common occurrence, however, as Shadow remarks that such a feat should be impossible.
Sonic Adventure 2
In Sonic Adventure 2, the fake Emerald was created by Tails sometime after he was awarded a Chaos Emerald by Station Square for defeating the Egg Walker. Using his research on this Emerald, he developed his own artificial Chaos Emerald, one with nearly the exact same properties, but explosive when used in machinery.
Tails eventually brought the fake Emerald onto the Space Colony ARK, developing a plan to place the Emerald into the Eclipse Cannon, destroying it and halting Dr. Eggman's plan to take over the world. Sonic the Hedgehog went off to execute this plan. Meanwhile, Eggman noticed that there was an extra Chaos Emerald signature in the vicinity, and that there must have been a fake. Sonic was later about to insert the Emerald into the cannon, when Eggman called him, threatening Amy Rose at gunpoint. Sonic soon arrived on the scene, figuring that he could easily hand Eggman the fake Emerald, save Amy, and destroy the Eclipse Cannon. However, Eggman, having already suspected that Sonic and his friends were planning to use a fake emerald to undo his plans due to detecting both energy signatures from his base earlier, called his bluff, with Tails unwittingly confirming the ruse as a result, and trapped the hedgehog in a capsule which he jettisoned into space.
Before the capsule could detonate, however, Sonic used Chaos Control with the fake Emerald to teleport back to the ARK. He then decided to finish the plan by inserting the fake Emerald into the Eclipse Cannon himself. On his way to the weapon, he crossed paths with Shadow and the two began a fight where Sonic used the fake Emerald to perform Chaos Control with. Afterward, Sonic managed to insert the fake Emerald into the Eclipse Cannon. causing disabling explosions across the cannon.
In other media
In Season 3, the Metarex initiated a plan by the name of Operation Duplicate in order for a number of fakes to be used for their Forestation Project - providing their new world of endless forests enough energy to last forever. These emeralds’ energies were ultimately consumed by a brief transformation used by Sonic the Hedgehog.
Hundreds of these Emeralds were mass produced with similar abilities but altered properties when compared to a normal Chaos Emerald. They could easily be crushed or disintegrate after strenuous use. These Emeralds were capable of inducing Chaos Control and could also initiate a super transformation in the form of Dark Sonic.
- In many older Sonic games, such as Sonic the Fighters and Sonic the Hedgehog Spinball, the number of Chaos Emeralds fluctuates. Many fans have attributed this to one or more fake Emeralds.
- When Team Dark uses their Team Blast, Chaos Inferno, there is a Chaos Emerald that is used to induce the move - even if the player has yet to collect any Emeralds. Many fans have presumed that Emerald was a fake, but canonically, it likely was the green Emerald that Team Dark obtained in the cutscene before the battle against Metal Sonic.
- In an unused texture found inside of the game files of Sonic Adventure 2, the Fake Emerald was depicted as white instead of yellow. This texture was supposed to be displayed onto Eggman's monitor when he finds out that Sonic and his friends have infiltrated the Space Colony ARK.
- Sonic Team USA (23 June 2001). Sonic Adventure 2. Dreamcast. Sega. Cutscene: The Space Colony "ARK" (Hero story). "Tails: It looks like it doesn't it? But in fact, it's a fake one that I created after researching the real Emerald! It has the same wavelength and properties but is less powerful than the real one. It's designed to reverse the energy field inside the Chaos Emeralds and blow up! It looks so real, even a machine can't tell the difference!"
- Sonic Team USA (23 June 2001). Sonic Adventure 2. Dreamcast. Sega. Cutscene: Cutscene 24 (Dark story). "Eggman: This is strange... it's showing energy readings from two separate Chaos Emeralds. Did they really think they could trick me with that fake Emerald?"
- Sonic Team USA (23 June 2001). Sonic Adventure 2. Dreamcast. Sega. Cutscene: Sonic in Trouble (Hero story). "Sonic: Handing over the fake Emerald, I can kill two birds with one stone."
- Sonic Team USA (23 June 2001). Sonic Adventure 2. Dreamcast. Sega. Area/Level: Shadow (boss). Cutscene: Last Chance (Hero story). "Shadow: It was a Chaos Emerald, wasn't it? But, there's no way you could have activated the Chaos Control using an Emerald that's fake."
- Sonic Team USA (23 June 2001). Sonic Adventure 2. Dreamcast. Sega. Cutscene: Sonic in Trouble (Hero story). "Eggman: You thought you could trick me with that fake Emerald, didn't you? / Tails: So... how did you know it wasn't the real one? / Sonic: Tails! / Eggman: Because you just told me, fox boy!"
- Sonic Team USA (23 June 2001). Sonic Adventure 2. Dreamcast. Sega. Cutscene: Last Chance (Hero story). "Sonic: I got it! Before the cannon fires, I'll slam dunk it in there!"