An obsidian hand ax crafted by an ancient human relative more than 1.2 million years ago.

An obsidian hand ax crafted by an ancient human relative more than 1.2 million years ago.

 Because it requires skill and knowledge, stone tool use among early hominins, the group that includes humans and the extinct species more closely related to humans than any other animal, can offer a window into the evolution of the human mind. A key advance in stone tool creation was the emergence of so-called workshops. At these sites, archaeologists can see evidence of hominins methodically and repeatedly crafting stone artifacts.

The newly analyzed trove of obsidian tools may be the oldest stone-tool workshop run by hominins on record. "This is very new in human evolution," study first author Margherita Mussi, an archaeologist at the Sapienza University of Rome and director of the Italo-Spanish archeological mission at Melka Kunture and Balchit, a World Heritage site in Ethiopia, told Live Science.

In the new study, the researchers investigated a cluster of sites known as Melka Kunture, located along the upper Awash River valley of Ethiopia. The Awash valley has yielded some of the best known examples of early hominin fossils, such as the famous ancient relative of humanity dubbed "Lucy."