The rocker spent weeks trying to track down the lost phone, but despite the best efforts of friends around the world, he has accepted he'll never see it again.

Appearing on The Jasta Show podcast recently, the guitarist said, "(It contained) 250 musical ideas and I was crushed. It didn't get backed up. And when it happened, I was bummed out for about two or three days.

"I just set it (down) somewhere and... It still might turn up. I'm hoping it will. To try to remember those riffs... I can only remember, like, eight of them. So I just chalked it down to maybe it just wasn't meant to be and I'll just move forward with it."

The podcast chat turned his friends into detectives and they started sending Hammett emails and texts helping him piece together when he last had the phone.

He recalls, "They were saying, 'When I was with you, when we were hanging out in Istanbul, you seemed to have it...'"

But Hammett is being philosophical about his missing phone and the lost riffs, adding, "I ask myself, maybe the universe is trying to tell me something. Maybe those bits of music were just not meant to be heard by anyone else. I don't know. Maybe my karma is just bad and I'm paying for bad behaviour in the past. I don't know."