Knuckles' emerald: Turquoise

The third level is Knuckles' level. He must travel through the Topical Jungle to this tune www.youtube.com/watch?v=kb9TKK… . It's sadder then Omega's one, but not as much as Tails' one. Knuckles is lost as his rival/buddy is dead. He is definitely Sonic's best friend after Tails and Rotor (if you're willing to count the SatAm canon too).

Turquoise is a mix of blue and green. The green shows that Knuckles is more focused on the mission then some of the other characters, but the blue shows his sadness at the loss of his friend.