There are 4 to 5 teenagers that wonder off into this forest and find an energy stone in the middle of it.

They step on it and it lights them up in different ways and gives them each a different power. And they can step on it again to magnify themselves power.

One of the girls turns bad and gets these other jock guys to join her and raise their power with the stone for evil.

I never watched the end of the movie, but I remember she got this tattle tale guy to almost commit suicide and call the police and blame two of the kids.

But I don't remember the name.

It's not from the 80's, but it sounds like The Source (2002) (http://www.imdb.com/title/tt0265787/).

Plot: A group of high school outcasts finally get even, but soon decide mere revenge is not enough in this supernatural horror film. Four teenagers who have long been the butt of jokes at their high school discover a strange and mysterious stone in the woods, which gives them mental and physical powers beyond those of ordinary people. Not surprisingly, the kids begin using their new skills to even the score with the bullies who have been making their lives miserable for years, but one of the teens begins going further than playing cruel but harmless pranks. Soon the kids realize their new powers could make them a force to be reckoned with, and their ambitions go beyond being the cool kids at school to running their town -- or perhaps the world. Also released as The Source, The Surge features Alice Frank, Mathew Scollon, Edward Deruiter, and Melissa Renee Martin. ~ Mark Deming, All Movie Guide

The source