Green axes and adzes made from metatuff - a metamorphic rock formed when volcanic ash is subjected to high heat and pressure - were in great demand across Neolithic northeastern Europe. Excavations at one of 40 identified workshops along the Shuya River near Lake Onega, about 300 kilometres northeast of St Petersburg in the Russian Republic of Karelia, have yielded 350,000 lithic finds, 84 percent of which are metatuff.
     Radiocarbon dating of organic matter associated with 77 Neolithic and Eneolithic sites in the region indicates this source was exploited starting around 6,000 to 5,000 years ago, before any evidence of agriculture or domesticated animals. The two known prehistoric quarries are estimated to have produced hundreds of thousands of tools. Analysis of hundreds of preforms and finished tools, their geographical distribution, and context, reveals a massive distribution network with long-distance trade to Finland and Sweden, Kazan and Eastern Siberia, more than 1,000 kilometres away.
     Requiring a specialised four-stage process, making the tools is a tedious process. Most are quite big and heavy. Some of the largest and finest specimens are found in a detached context, leading to speculation they were ritual offerings, but not all these artefacts are in pristine condition; less developed pieces exhibiting heavy wear are commonly found in mundane contexts. Metatuff was not the only raw material available. Tools made of flint, points made of slate, hammered native copper artefacts, amber jewelry, and more have been identified.

Edited from Haaretz.com (7 December 2021)