Counterclockwise from top: obsidian, pumice (lower left), and rhyolite (lower right)
Rainbow obsidian
Snowflake obsidian
Snowflake obsidian.
Pig carved in snowflake obsidian, 10 centimeters (4 in) long. The markings are spherulites.
from Lake County, Oregon
Obsidian arrowhead
A polished snowflake obsidian on a white background
A polished snowflake obsidian
Obsidian from Panum Crater, Mono Lake.
Obsidian talus at Obsidian Dome, California
Pile of obsidian on Newberry Obsidian flow, central Oregon
Glass Mountain, a large obsidian flow at Medicine Lake Volcano