Recent trip to Glass Mountain, Modoc County, California

 

Medicine Lake in the bottom of the Medicine Lake Caldera, with Mt. Shasta to the west.

Wild Obsidian

A geology professor explains the rocks

A streak of obsidian.

Most of this was burped up about 950 years ago, a blink in geologic time.  In fact, there is some evidence that there was mild volcanic activity as recently as 1910.

The trail.

A streak of obsidian embedded in pumice.  So cool.