Crystals have always been a running theme ever since the first Final Fantasy entry -- it's sorta that common thing that keeps on reappearing; like summons, weapon names, and character archetypes. Well, Square-Enix is currently teasing a "mystery game" on a website that has a trailer (you can visit it here) with some of those elements presented in text form:
At this point there's really nothing to know about this "mystery" project, but some people have recently discovered registered domain name by the company that reads "Crystal Conquest". GameTrailers seems to think there's some correlation between this new title and the Chrono series because of "C is coming" introduction, but we're leaning more towards an original game.
We'll post up any info when it hits the web.