A German woman has emerged unscathed after she picked up what she thought was a chunk of amber, but turned out to be WW2-era white phosphorous which ignited in her pocket.

The 41-year-old was walking on Elbe’s riverbank in Wedel, near Hamburg, when she pocketed what appeared to be the precious stone. Upon drying, it quickly ignited in her jacket. Passers-by and firefighters to intervene.

According to the local authorities, the phosphorus came from a WW2 incendiary device. Passersby intervened and called firefighters, who quickly extinguished the blaze.

Unexploded ordnances are frequently unearthed in Germany during construction works, in private gardens or in rivers, or through the study of aerial images.

The largest post-war bomb disposal operation occurred in December 2016, when a 1.8 ton bomb dropped by Britain’s Royal Air Force was found in the city of Augsburg, prompting the evacuation of over 54,000 people on Christmas Day.

Between 1940 and 1945, US and British forces targeted German cities with over a million tons of bombs, mostly dropped on industrial and strategic areas such as the Ruhr, Cologne, Hamburg, Dresden and Berlin.

Experts estimate that a quarter of a million of those unexploded ordnances still lie underground, while around 55,00 of them are defused each year.