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Introduction to Obsidian

What is Obsidian?

Obsidian is a naturally occuring volcanic glass formed when felsic lava extruded from a volcano cooled rapidly.

Composition of Obsidians

Pure Obsidian is composed of approximately 70% silicon dioxide, also known as silica. Chemically, Obsidian closely resembles granite and rhyolite. While pure Obsidian is dark in appearance, the colour varies depending on the presence of impurities. For instance, iron and magnesium gives obsidian a dark green to brown shade. An important property of very viscous lava is that it does not mix well, which means that no obsidian from two different sources is identical. More so, each sample of obsidian can be traced to a specific volcanic eruption.


Types of Obsidian Tools with Water Color Paintings by (right)

















Spear Points