Chinese researchers have discovered a rare stone made of molten lava that could be broken up to create cutting tools by prehistoric ancestors more than 20,000 years ago.

The cone-shaped stone which had numerous marks where pieces had been chipped off to make cutting instruments like axes, knives and arrowheads was found in Helong City, located in the northeast of China’s Jilin Province.

Researchers, who confirmed that this artefact is more than 20 millennia old, dating back to the Paleolithic period, believe its discovery is very important to better understand how man’s ancestors lived and used nature’s resources to their advantage.

According to Zhang Fuyou, a researcher at the Chinese provincial institute for culture and history, the pre-historic block is an obsidian stone, also known as volcanic glass, which is formed by the rapid solidification of lava.

He believes this one was originates from the lava residues of the Changbai Mountain volcano, which is in close proximity of the location where it was discovered. Xu Ting, an expert at the provincial institute of cultural relics and archaeology said: “The artefact is cone-shaped with a length of 53 centimetres and a weight of 16.3 kilograms.

The maximum diameter of the cone reaches 16 centimetres.” The stone reportedly had 14 artificially made scars along its outer surface.

The obsidian stone is now part of a temporary collection in the Helong Museum where it can be admired by history-loving visitors.