The parents of a teenager who died at a rock festival in the Highlands at the weekend have blamed his death on a freely-available "legal high" which mimics the effects of ecstasy.

In a statement, the family of Alex Heriot, a 19-year-old media student from Edinburgh who died at Rockness on Saturday night, urged other teenagers to avoid experimenting with legal highs, or any other drug which could put their life at risk.

"Alex was not a habitual drug user," they said. "We know that young people dabble in drugs and Alex had been warned to steer clear. Please, please be aware that certain drugs can kill and please don't be the next youngster to leave their family bereft."

Describing their son as "beautiful both on the outside and the inside where it mattered most", they said Heriot was "happy, caring, kind, loyal and affectionate." He was a young man who loved life, they said, and immensely popular.

"The fact that we will not be seeing him wandering around the house with his laptop playing his music, teasing his sister and asking if there was any food and could he have a bus fare please is unbearable," they added.

Heriot died in Raigmore hospital in Inverness after being taken ill in the main arena at Rockness, after taking the legally-available psychotropic drug Benzo Fury. He was taken to the festival's medical tent, and then transferred to hospital. He died there on Sunday morning.

Two other teenagers from Edinburgh, who are understood to have known Heriot, were also taken ill and hospitalised after taking the drug. They were discharged on Sunday. Urgent warnings were issued by police to avoid using "legal highs", laboratory-designed drugs which can be openly bought over the internet.

The family said Heriot, from Portobello, Edinburgh had been passionate about music and festivals, and had obviously wanted to get the most out of his time at the festival. Clearly distressed by his death, they were careful not to condemn teenagers who used illegal drugs.

"Alex was attending a music festival which he had been looking forward to enormously. As a young man who enjoyed life it was unfortunate he chose to experiment with a drug that had such a catastrophic effect on his system," they said.

"We are devastated that we have lost him but anything he did, in every area of his life, was done with good intent, in this case to get the most out of his festival experience."

Northern Constabulary have so far refused to directly link Heriot's death with the drugs he took until they receive a detailed toxicological report and post mortem test results, which could take several weeks to complete. But they confirmed that the drug use was a major line of enquiry.

David Liddell, of the drug education and counselling agency Scottish Drugs Forum, said there was a clear case for banning Benzo Fury, since it seemed to have very similar effects as ecstasy but was extremely difficult to know what its ingredients might be.

But he warned that controlling legal highs had proven very difficult, because of their continually changing nature and ingredients. The best advice to teenagers was to avoid them at all times.

"There's no easy solution to any of it," Liddell said. "We know that the chemical laboratories of China and elsewhere probably have ten new compounds to bring on stream. It's a moving target. No-one has yet come up a better way of dealing with this."