A woman is being treated for second and third degree burns after rocks collected on a beach burst into flames in her pocket.
Lyn Hiner was at a beach in southern California with her children, when they collected green and orange-coloured rocks for her.
Mrs Hiner put them in her pocket before leaving the beach but, as she and husband Rob Hiner were preparing to go out later that night, the rocks exploded in her shorts.
The pair appeared on Good Morning America from the burns centre at Santa Ana, California, and, according to ABC News, explained: "All of a sudden something hot on my leg just sort of started to bother me so I started thinking it was a bug bite, so I started slapping it and the next thing I know my pants were on fire."
Rob added: "It was just this bright intense flame. We didn't know what it was. Our first response was just to try to pat it out.
"But, In trying to pat it out, it wasn't going out so the next thing was just to try and drop and roll and eventually we just tried to tear her shorts off and got them off of her."
Mrs Hiner's doctor, Andrea Dunkelman, said: "I've never seen anything like this. She has third-degree burns, which means that it's been burned all the way through her skin to her underlying tissue, her fat. We treated her by placing skin grafts from her thigh to that area."
According to USA Today, scientists investigating the incident say the seven rocks Hiner's daughters bought back for her contained traces of phosphorous, the chemical found on the tips of matches.
San Diego State University geologist Pat Abbott told ABC News: "I know the orange is not part of the rock. It's not natural. It's human made."
Read more at ABC News