Black Knight in Power Rangers?

I can't remember which one,but in an old series of Power Rangers, there was this additional Ranger who was Black, had yellow horns, and a glowing turquoise hexagon chest piece (much like iron man). For the sake of Nostalgia, I've been wanting to rewatch the episodes with him, but I can't remember the series or name of him!!! so if you guys please know, leave me an answer, thanks! :)