Obsidian rock from Obsidian Cliff, YNP.

Detailed Description
Close view of rocks from from Obsidian Cliff. This outcrop exposes the interior of a thick rhyolite lava flow erupted about 180,000 years ago.
Sources/Usage
Public Domain.
Close view of rocks from from Obsidian Cliff. This outcrop exposes the interior of a thick rhyolite lava flow erupted about 180,000 years ago.
Public Domain.