Early Humans Favored Fossil-Rich Rock for Tools
Stone artifacts from three Lesvos sites show toolmakers relied heavily on fossil-bearing siliceous sinter.
Updated on Nov. 7, 2026 in Geology
Researchers Elli Karkazi, Nena Galanidou and Andreas Magganas examined 1,413 artifacts from Rodafnidia, Glyfias and Bi Tsesme on the Greek island of Lesvos. Most were made from fossil-bearing siliceous sinter, a rock containing preserved traces of plants, algae and tiny shelled organisms.
Why it matters
The findings show early humans selected stone for specific mechanical properties, with fine quartz crystals likely helping the rock break in a controlled way. Gathering the material close to the sites suggests toolmakers knew their local geology well.
The analysis drew on 980 excavated objects and 433 surface finds collected from 2010 to 2021, with fossil grains making up an estimated 40% to 60% of the sinter. The precise ages of the oldest deposits remain unsettled, with a possible date near 476,000 years ago.
The players
Elli Karkazi
Karkazi is a researcher who co-led the analysis of the Rodafnidia, Glyfias and Bi Tsesme stone tool collections.
Nena Galanidou
Galanidou is an archaeologist who co-authored the study of prehistoric stone tools from the Lesvos sites.
The details
Under the microscope, the researchers found preserved plant tissue, algae and shelled organisms within the rock. Loose sinter pieces in site deposits suggest toolmakers gathered much of the material nearby, producing handaxes, cleavers, smaller tools and large stone cores.
Timeline
Artifacts were gathered from the sites between 2010 and 2021.
Minimum ages of the excavated deposits were dated to roughly 164,000 to 272,000 years ago.
Big Picture
The Lesvos findings extend the documented record of Middle Pleistocene stone tool-making, which has been studied extensively at sites in Africa and the Levant. Comparable methods at those regions place the Aegean site within a wider pattern of early human material selection.
The findings give scientists a clearer picture of how early humans read the local landscape to find usable rock. They also show how material properties like fine quartz crystals can guide the choice of tools for everyday work.
The takeaway
Early toolmakers chose stone based on how it broke, not only on how easily it could be found. Understanding local geology helped them shape reliable tools from materials close at hand.
Further reading
Explore more research in Geology to see how rock composition shaped early human technology.
