If it's the one I'm thinking of, it was a pilot for a series that never aired called "Island City" (1994). Does this sound familiar?
In the future, humanity develops a "fountain of youth" drug, but as many people around the world begin to take it, most begin to mutate into a barbaric proto-humanoid state. The few people immune to this side-effect of the drug band together and live in a futuristic city while the mutants live in the vast wasteland outside its gates.
Citizens of the city wore a colored crystal on their sternum and could only mate with other citizens of the same color, which was based on the individual's genetic makeup. Progeny that resulted from breeding outside of your prescribed color would have the genetic mutation that, when combined with the "fountain of youth" drug, created the race of proto-humanoids.
Thanks to the wonders of YouTube, here's the intro. In some of the scenes, their uniforms are unbuttoned just enough that you can see the crystals embedded in the chest.
The show had some popular 90's actors in it but never took off. I didn't realize until I looked just now, but the main character was played by Kevin Conroy, widely famous as the voice of Batman.