A teen suicide and a schoolgirl stabbing. Two separate tragedies in Adelaide schools.

On Thursday morning, a 16-year-old Adelaide girl went to school as normal. She likely had her backpack and her school uniform and was carrying the books she needed.

But, when she arrived at Trinity College North in Evanston South, this teenager had different intentions. Hidden in her bag there was also a knife, which she used  – allegedly – to stab a fellow student in the stomach, arm and leg.

A 15-year-old girl was taken to hospital with minor injuries, AAP reports.

And the 16-year-old has been charged with aggravated assault causing harm, and is expected to face court next month.

School principal Nick Hately said the altercation between the two year 10 girls led to the alleged stabbing.

“Acts of violence are incredibly rare so this incident is very confronting for our community,” he said in a letter to parents.

This comes three days after 13-year-old schoolgirl Libby Bell took her own life after being bullied in person and online, also in Adelaide.

Her family claims she suffered years of cyber bullying through Facebook, Instagram and Snapchat, as well as physical abuse in the schoolyard, News Corp reports.

“Those that bullied you, and your so-called friends that didn’t speak up, they failed you gorgeous girl and we won’t stop fighting for you until they are held accountable,” mother Crystal Bell posted to Facebook.

The two heartbreaking stories are a reflection of something bigger: a bullying problem in Australian schools so severe, it's leading to violence. And so difficult to manage, because it's being played out largely on social media.

In a bid to take action, Australian Conservatives state MP Dennis Hood says he will work to introduce bullying-specific legislation in South Australia to make it easier to crackdown on long term harassment.

Mr Hood says that the proposed legislation will be modelled on laws introduced in Victoria in 2011 which makes serious bullying a crime punishable by up to 10 years imprisonment.

"Since Brodie's Law was introduced in Victoria, almost 60 people have been charged with bullying, which is proof of its effectiveness," Mr Hood said.

Mr Hood said according to survey figures by the South Australian education department, around 5,000 students a week are bullied in SA schools.

Readers seeking support are urged to contact Beyond Blue on 1300 224 636 or Lifeline on 13 11 14.

To read about a popular app that's turned into a bullying platform, click here. 

To read about Ian Thorpe's experience with bullying, click here.

To read about the Safe Schools program, click here.

LISTEN: Do parents have to crack down on teens?