Need help remembering the movie name

My memory of this movie is very vague so I apologize if I'm way off base but I'll try to be specific as possible.

It's a Sci-Fi movie about a group of people, miners or scientists maybe, that find this purple crystal that has energy pulsing out of it. One of the guys ends up spending too much time around it and he starts changing him mentally mostly but there were some physical changes, like his knuckles became more pronounced and started sparking when he rubbed them against each other. Another of the guys ends up getting attached to the crystal too and the first guy uses him for awhile to attack the others but eventually offs him as well. I want to say there were some recognizable actors in the movie but I can't remember them.

Thank you in advance.