What is obsidian?
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What is Obsidian?

Obsidian
Obsidian spear point, from New Mexico
(National Park Service)

Obsidian is a kind of volcanic glass. It is shiny and black, and you get it from the area around volcanoes. When a volcano erupts, it spits out a bunch of melted rock.

If the melted rock is mostly silica, and it cools just right, at the right speed, it can turn into naturally made glass. That is obsidian.

Obsidian is very useful, because it will hold a very sharp edge, so it makes good knives and arrowheads and fishhooks and so forth. Even today some surgeons still use obsidian knives in eye surgery.

In the Stone Age a lot of people wanted obsidian tools, because they were sharper than flint. But you could not find obsidian just anywhere. So one of the first things that people traded for, when they were just beginning to trade, was obsidian.

Learn by doing: check out some obsidian at a rocks and gems store
More about stone tools: flint

Bibliography and further reading about obsidian:

Archaeology : Uncovering the Mysteries of Our Past, by Richard Panchyk (2001). With twenty-five projects, like counting tree rings, and serializing cars from photographs.

Lithics (Cambridge Manuals in Archaeology), by William Andrefsky (1998). A specialist's manual for studying all kinds of stone tools.

Production and Exchange of Stone Tools : Prehistoric Obsidian in the Aegean, by Robin Torrence (1986). Unfortunately out of print.

Or check out the obsidian article in the Encyclopedia Britannica.

More about stone tools: flint
More about volcanoes
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Professor Carr

Karen Eva Carr, PhD.
Assoc. Professor Emerita, History
Portland State University

Professor Carr holds a B.A. with high honors from Cornell University in classics and archaeology, and her M.A. and PhD. from the University of Michigan in Classical Art and Archaeology. She has excavated in Scotland, Cyprus, Greece, Israel, and Tunisia, and she has been teaching history to university students for a very long time.

Professor Carr's PSU page

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Now that the weather's nice, try some of these outdoor activities! How about bicycle polo, or archery for a Medieval Islam day? Or kite flying or making a compass for a day in Medieval China? How about making a shaduf for a day in Ancient Egypt? Holding an Ancient Greek Olympic Games or a medieval European tournament? Building a Native American wickiup?