Obsidian is a beautiful volcanic glass that forms when molten rock material cools very rapidly, and was a favourite among ancient people worldwide for creating tools. It forms on the earth’s surface along the edges of a volcanic dome or lava flow, such as where lava contacts water or cool air. It is most commonly opaque black but can occur in many variations such as brown, purple and green – as well as some other colours – usually caused by trace elements or other inclusions.
Obsidian is found in many locations across the globe, confined to areas of geologically recent volcanic activity. It is rare to find any obsidian older than a few million years because the glassy rock is destroyed by weathering. Greece is not the only place where significant deposits are found, they are also in Argentina, Canada, Chile, Ecuador, Guatemala, Hungary, Iceland, Indonesia, Italy, Japan, Kenya, Mexico, New Zealand, Peru, Russia, United States and more!
Obsidian breaks with a conchoidal fracture – meaning it breaks into pieces with curved surfaces, producing rock fragments with very sharp edges. From what we know today, the manufacture of obsidian tools by humans dates back to the stone age. Enormous volumes of obsidian flakes at a site reveal the presence of ancient ‘tool factories’. Flakes are the debris left behind when making blades, and cores – such as this one – are the central piece of obsidian used to take the blades from. Producing arrowheads, spear points, knife blades and scrapers, obsidian was so valued by ancient peoples that it was mined, transport