Learn more about the colorful and shiny stones that were turned into tools as many as 40,000 years ago, which were sometimes ...

A new study has shown that as early as the Stone Age, people in Africa traveled long distances to procure colorful stone, the ...

Chalcedony can be found in various colours, including white, grey, blue, lavender, pink, brown, green, and black. The colouration is often due to the presence of trace elements or inclusions.

Photo: Gregor Bader The Mgwayiza Valley in Eswatini A new study has shown that as early as the Stone Age, people in Africa ...

The geochemistry of agate and chalcedony in volcanic rocks represents an intricate record of silica precipitation and crystallisation processes occurring under variable thermal and chemical ...